testing/headscale: upgrade to 0.16.3
https://github.com/juanfont/headscale/releases/tag/v0.16.3
- ec5acf7 Add ability to connect to PostgreSQL via unix socket
- 0a5db52 Add ability to connect to PostgreSQL via unix socket
- 8557bce Added changelog entries for 0.16.x
- cc3de7e Fix error decoding claims (#744)
- 7197ade Merge branch 'main' into postgres-connection-string
- e1a95e2 Merge pull request #734 from vtrf/postgres-connection-string
- 193b421 Merge pull request #739 from juanfont/updated-changelog-0.16.2
- f738031 Merge pull request #747 from juanfont/fix-oidc
- 287309b Update changelog