- remove mention of MyGet.org since we currently do not have available nightly builds
- we hope to restore this availability soon though it's likely builds will remain infrequent
* Move to a current .NET SDK
- cherry-picked from release/3.2.8 commit ffbf707ddd
* Rebrand to v3.2.9 / v5.2.9
- cherry-picked from release/3.2.8 commit bc83a3a7ec (#298)
- then, switched to 3.2.9 instead of 3.2.8
- reformat README.md
- merge 'Git tag' and 'Git branch' columns
- remove old v3.2.4 / v5.2.4 information
- add v3.2.7 / v5.2.7 information
- match combination of eb1bfe51a1 and 986889d81c i.e. the upgrade to 5.2.5 / 3.2.5 Preview1
- also change README.md to use "Web API 5.x" instead of "Web API 2.x"