Update ruby

Changes:

- https://github.com/docker-library/ruby/commit/5e9c75e: Update to 2.7.0-preview3
- https://github.com/docker-library/ruby/commit/4ba4a2d: Merge pull request https://github.com/docker-library/ruby/pull/298 from sdwolfz/ruby_preview2
- https://github.com/docker-library/ruby/commit/7c4fcc4: Update 2.7 to preview2 version

library/ruby

@@ -4,19 +4,19 @@ Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/ruby.git
 
-Tags: 2.7.0-preview2-buster, 2.7-rc-buster, rc-buster, 2.7.0-preview2, 2.7-rc, rc
+Tags: 2.7.0-preview3-buster, 2.7-rc-buster, rc-buster, 2.7.0-preview3, 2.7-rc, rc
 Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: 1dd5c255325fa0d5c3761f5238bbe1a9f50e9596
+GitCommit: 5e9c75e51671c0ed661b8654618596602a21fae0
 Directory: 2.7-rc/buster
 
-Tags: 2.7.0-preview2-slim-buster, 2.7-rc-slim-buster, rc-slim-buster, 2.7.0-preview2-slim, 2.7-rc-slim, rc-slim
+Tags: 2.7.0-preview3-slim-buster, 2.7-rc-slim-buster, rc-slim-buster, 2.7.0-preview3-slim, 2.7-rc-slim, rc-slim
 Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: 1dd5c255325fa0d5c3761f5238bbe1a9f50e9596
+GitCommit: 5e9c75e51671c0ed661b8654618596602a21fae0
 Directory: 2.7-rc/buster/slim
 
-Tags: 2.7.0-preview2-alpine3.10, 2.7-rc-alpine3.10, rc-alpine3.10, 2.7.0-preview2-alpine, 2.7-rc-alpine, rc-alpine
+Tags: 2.7.0-preview3-alpine3.10, 2.7-rc-alpine3.10, rc-alpine3.10, 2.7.0-preview3-alpine, 2.7-rc-alpine, rc-alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: 1dd5c255325fa0d5c3761f5238bbe1a9f50e9596
+GitCommit: 5e9c75e51671c0ed661b8654618596602a21fae0
 Directory: 2.7-rc/alpine3.10
 
 Tags: 2.6.5-buster, 2.6-buster, 2-buster, buster, 2.6.5, 2.6, 2, latest