- Update README.md to point to v1beta3 spec docs.
- Remove provider testdata which had old API version and is no longer
used in any test.
- Update Provider v1beta2 spec docs to use Alert v1beta2.
- Update Provider v1beta3 spec docs to use v1beta3 API in all the
code snippets.
Signed-off-by: Sunny <darkowlzz@protonmail.com>