Upgrade golang.org/x/net from v0.15.0 to v0.17.0

[ptodev]

This issue fixes CVE-2023-39325. This is the security report on the main branch, prior to this change:

└─▪ trivy repo https://github.com/grafana/agent --branch main --timeout 20m0s
2023-10-12T12:08:51.568+0100	INFO	Vulnerability scanning is enabled
2023-10-12T12:08:51.568+0100	INFO	Secret scanning is enabled
2023-10-12T12:08:51.568+0100	INFO	If your scanning is slow, please try '--scanners vuln' to disable secret scanning
2023-10-12T12:08:51.568+0100	INFO	Please see also https://aquasecurity.github.io/trivy/v0.45/docs/scanner/secret/#recommendation for faster secret detection
Enumerating objects: 41803, done.
Counting objects: 100% (41803/41803), done.
Compressing objects: 100% (20803/20803), done.
Total 41803 (delta 21196), reused 36780 (delta 17362), pack-reused 0
2023-10-12T12:12:44.916+0100	INFO	Number of language-specific files: 3
2023-10-12T12:12:44.916+0100	INFO	Detecting gomod vulnerabilities...
2023-10-12T12:12:44.921+0100	INFO	Detecting yarn vulnerabilities...

go.mod (gomod)

Total: 2 (UNKNOWN: 0, LOW: 0, MEDIUM: 2, HIGH: 0, CRITICAL: 0)

┌─────────────────────────┬────────────────┬──────────┬────────┬─────────────────────────────────────┬───────────────┬──────────────────────────────────────────────┐
│         Library         │ Vulnerability  │ Severity │ Status │          Installed Version          │ Fixed Version │                    Title                     │
├─────────────────────────┼────────────────┼──────────┼────────┼─────────────────────────────────────┼───────────────┼──────────────────────────────────────────────┤
│ github.com/grafana/loki │ CVE-2021-36156 │ MEDIUM   │ fixed  │ 1.6.2-0.20231004111112-07cbef92268a │ 2.3.0         │ Path traversal in Grafana Loki               │
│                         │                │          │        │                                     │               │ https://avd.aquasec.com/nvd/cve-2021-36156   │
├─────────────────────────┼────────────────┤          │        ├─────────────────────────────────────┼───────────────┼──────────────────────────────────────────────┤
│ golang.org/x/net        │ CVE-2023-39325 │          │        │ 0.15.0                              │ 0.17.0        │ rapid stream resets can cause excessive work │
│                         │                │          │        │                                     │               │ (CVE-2023-44487)                             │
│                         │                │          │        │                                     │               │ https://avd.aquasec.com/nvd/cve-2023-39325   │
└─────────────────────────┴────────────────┴──────────┴────────┴─────────────────────────────────────┴───────────────┴──────────────────────────────────────────────┘

This is the report after the change:

└─▪ trivy repo https://github.com/grafana/agent --branch ptodev/fix-cve --timeout 20m0s
2023-10-12T12:17:46.591+0100	INFO	Vulnerability scanning is enabled
2023-10-12T12:17:46.591+0100	INFO	Secret scanning is enabled
2023-10-12T12:17:46.591+0100	INFO	If your scanning is slow, please try '--scanners vuln' to disable secret scanning
2023-10-12T12:17:46.591+0100	INFO	Please see also https://aquasecurity.github.io/trivy/v0.45/docs/scanner/secret/#recommendation for faster secret detection
Enumerating objects: 41803, done.
Counting objects: 100% (41803/41803), done.
Compressing objects: 100% (20803/20803), done.
Total 41803 (delta 21196), reused 36780 (delta 17362), pack-reused 0
2023-10-12T12:21:51.215+0100	INFO	Number of language-specific files: 3
2023-10-12T12:21:51.215+0100	INFO	Detecting gomod vulnerabilities...
2023-10-12T12:21:51.216+0100	INFO	Detecting yarn vulnerabilities...

go.mod (gomod)

Total: 1 (UNKNOWN: 0, LOW: 0, MEDIUM: 1, HIGH: 0, CRITICAL: 0)

┌─────────────────────────┬────────────────┬──────────┬────────┬─────────────────────────────────────┬───────────────┬────────────────────────────────────────────┐
│         Library         │ Vulnerability  │ Severity │ Status │          Installed Version          │ Fixed Version │                   Title                    │
├─────────────────────────┼────────────────┼──────────┼────────┼─────────────────────────────────────┼───────────────┼────────────────────────────────────────────┤
│ github.com/grafana/loki │ CVE-2021-36156 │ MEDIUM   │ fixed  │ 1.6.2-0.20231004111112-07cbef92268a │ 2.3.0         │ Path traversal in Grafana Loki             │
│                         │                │          │        │                                     │               │ https://avd.aquasec.com/nvd/cve-2021-36156 │
└─────────────────────────┴────────────────┴──────────┴────────┴─────────────────────────────────────┴───────────────┴────────────────────────────────────────────┘

I intend to fix CVE-2021-36156 in a separate pull request.

I believe this is a backwards compatible change which is not user facing, so I'm not updating the changelog. As far as I can tell in the "net" package's release tags, the recent changes to it are minor.

[mattdurham]

Lgtm