Update ruby

Changes:

- https://github.com/docker-library/ruby/commit/886df6b: Update to 3.0.0-preview2

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: 3.0.0-preview1-buster, 3.0-rc-buster, 3.0.0-preview1, 3.0-rc
+Tags: 3.0.0-preview2-buster, 3.0-rc-buster, 3.0.0-preview2, 3.0-rc
 Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, mips64le, ppc64le, s390x
-GitCommit: 57a8df4f141840757a74c6caf8d8bae7010cc512
+GitCommit: 886df6b547e4c61c113ba05dfd88eff4d94de9b4
 Directory: 3.0-rc/buster
 
-Tags: 3.0.0-preview1-slim-buster, 3.0-rc-slim-buster, 3.0.0-preview1-slim, 3.0-rc-slim
+Tags: 3.0.0-preview2-slim-buster, 3.0-rc-slim-buster, 3.0.0-preview2-slim, 3.0-rc-slim
 Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, mips64le, ppc64le, s390x
-GitCommit: 57a8df4f141840757a74c6caf8d8bae7010cc512
+GitCommit: 886df6b547e4c61c113ba05dfd88eff4d94de9b4
 Directory: 3.0-rc/buster/slim
 
-Tags: 3.0.0-preview1-alpine3.12, 3.0-rc-alpine3.12, 3.0.0-preview1-alpine, 3.0-rc-alpine
+Tags: 3.0.0-preview2-alpine3.12, 3.0-rc-alpine3.12, 3.0.0-preview2-alpine, 3.0-rc-alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: 57a8df4f141840757a74c6caf8d8bae7010cc512
+GitCommit: 886df6b547e4c61c113ba05dfd88eff4d94de9b4
 Directory: 3.0-rc/alpine3.12
 
 Tags: 2.7.2-buster, 2.7-buster, 2-buster, buster, 2.7.2, 2.7, 2, latest