Update mysql

Changes:

- https://github.com/docker-library/mysql/commit/7397711: Update to 5.7.30-1debian10
- https://github.com/docker-library/mysql/commit/d2ba5f1: Update to 5.6.48-1debian9
- https://github.com/docker-library/mysql/commit/fef5114: Update to 8.0.20-1debian10

library/mysql

@@ -4,14 +4,14 @@ Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/mysql.git
 
-Tags: 8.0.19, 8.0, 8, latest
-GitCommit: fcc68c84b7d30cf1ac2b4aed835425ad8311b440
+Tags: 8.0.20, 8.0, 8, latest
+GitCommit: fef511444a9d2867c9e4e20f5b4062bc071c20a2
 Directory: 8.0
 
-Tags: 5.7.29, 5.7, 5
-GitCommit: fcc68c84b7d30cf1ac2b4aed835425ad8311b440
+Tags: 5.7.30, 5.7, 5
+GitCommit: 7397711170daed7ebba3bf373af143e5179906fc
 Directory: 5.7
 
-Tags: 5.6.47, 5.6
-GitCommit: fcc68c84b7d30cf1ac2b4aed835425ad8311b440
+Tags: 5.6.48, 5.6
+GitCommit: d2ba5f1fd5c1f4002253b80575de9c759d22bb1e
 Directory: 5.6