Update to version 2.8.0 to fix bsc#1197821 (only use of TLS 1.2 required)

- Update to version 2.8.0:
* Update README so the release pipeline works properly.
* Make this releaes a beta release first.
* [2.8] Release artifacts
* release workflow
* Apply suggestions from code review
* Prepare for v2.8.0 release
* [release/2.7] vendor: github.com/opencontainers/image-spec v1.0.2
* manifest: validate document type before unmarshal
* [release/2.7] vendor: github.com/golang-jwt/jwt v3.2.1
- Drop merged patchs
* 0001-Fix-s3-driver-for-supporting-ceph-radosgw.patch
* 0002-Relax-filesystem-driver-folder-permissions-to-0777-cont.patch
* 0003-Support-external-redis-sentinel-cluster.patch
* 0004-Make-ipfilteredby-not-required.patch