Update mysql

Changes:

- https://github.com/docker-library/mysql/commit/38510a2: Update to 5.6.44-1debian9
- https://github.com/docker-library/mysql/commit/26380f3: Update to 5.7.26-1debian9
- https://github.com/docker-library/mysql/commit/130bd8e: Update to 8.0.16-1debian9

library/mysql

@@ -4,16 +4,16 @@ Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/mysql.git
 
-Tags: 8.0.15, 8.0, 8, latest
-GitCommit: a7a737f1eb44db467c85c8229df9d886dd63460e
+Tags: 8.0.16, 8.0, 8, latest
+GitCommit: 130bd8e46a3da1adfc1732a08c70673e20aa5977
 Directory: 8.0
 
-Tags: 5.7.25, 5.7, 5
-GitCommit: bb7ea52db4e12d3fb526450d22382d5cd8cd41ca
+Tags: 5.7.26, 5.7, 5
+GitCommit: 26380f33a0fcd07dda35e37516eb24eaf962845c
 Directory: 5.7
 
-Tags: 5.6.43, 5.6
-GitCommit: c0454b9e0ede6050deb66e2aabbc213b11b3eefe
+Tags: 5.6.44, 5.6
+GitCommit: 38510a26f56f429817da7cabf5c772756faa5e55
 Directory: 5.6
 
 Tags: 5.5.62, 5.5