Merge pull request oauth2-proxy#748 from oauth2-proxy/release-6.1.1

Prepare CHANGELOG for v6.1.1 release

Merge pull request oauth2-proxy#741 from oauth2-proxy/release-6.1.0

Prepare changelog for v6.1.0 release

Merge pull request oauth2-proxy#641 from oauth2-proxy/release-v6.0.0

Update changelog ready for release v6.0.0

Update changelog for 5.1.1 release (oauth2-proxy#525)

Merge pull request oauth2-proxy#463 from pusher/release-5.1.0

Update Changelog for Release 5.1.0

Merge pull request oauth2-proxy#368 from pusher/advisory-notes

Open redirect (security vulnerability) notes

Update CHANGELOG for v4.1.0 (oauth2-proxy#323)

Merge pull request oauth2-proxy#247 from pusher/release-v4.0.0

Update changelog for v4.0.0 release

Merge pull request oauth2-proxy#123 from pusher/release-3.2.0

Update changelog for release v3.2.0

Merge pull request oauth2-proxy#50 from pusher/release-v3.1.0

Update release notes for v3.1.0