update to bioconda-utils v3.2.0, remove defaults, switch to .conda package format

[mbargull]

Changes since bioconda-utils v2.15.1:

⚠ BREAKING CHANGES

• Separate docs-only requirements (#986)
• Remove defaults channel dependency (#985)

Miscellaneous Chores

• Remove defaults channel dependency (#985) (eb043dc)
• Separate docs-only requirements (#986) (09d108e)

Features

• Update base-glibc-*-bash images to 3.1 (#996) (e7c6ca0)

• Update dependencies to latest versions (#992) (8c0fe35)

Bug Fixes

• Pass pkg_format to container-based build (#994) (e3f23ed)

refs:

• https://github.com/bioconda/bioconda-utils/releases/tag/v3.2.0
• https://github.com/bioconda/bioconda-utils/releases/tag/v3.1.0
• https://github.com/bioconda/bioconda-utils/releases/tag/v3.0.0
• Update bioconda-utils to 3.2.0 bioconda-recipes#48214

---

Common config changes:

• Set pkg_format=2 (i.e., build .conda not .tar.bz2)
• Remove defaults channel

[mbargull]

* Set `pkg_format=2` (i.e., build `.conda` not `.tar.bz2`)

This is postponed for now via f761183