github: Update test workflow (#5)

* github: Update test workflow

### Changed
- Test workflow to: 
  - target main branch after branch rename
  - target Go 1.21 + 1.22

* github: Target latest Go version too

.github/workflows/go.yml

@@ -2,16 +2,16 @@ name: Go
 
 on:
   push:
-    branches: [ "master" ]
+    branches: [ "main" ]
   pull_request:
-    branches: [ "master" ]
+    branches: [ "main" ]
 
 jobs:
 
   build:
     strategy:
       matrix:
-        go: ['1.19', '1.20']
+        go: ['1.21', '1.22', '1']
 
     runs-on: ubuntu-latest
     steps: