Update bash

Changes:

- https://github.com/tianon/docker-bash/commit/4f0b1f9: Update to commit d37a47224aa80aaddc13e415886a698a8f8fde2e

library/bash

@@ -3,9 +3,9 @@
 Maintainers: Tianon Gravi <[email protected]> (@tianon)
 GitRepo: https://github.com/tianon/docker-bash.git
 
-Tags: devel-20200609, devel
+Tags: devel-20200615, devel
 Architectures: amd64, arm32v6, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: eeeeb03eb017d1573677b98bea7bc3a2e079a848
+GitCommit: 4f0b1f90c31e844616b6da2641a00fd33b05879a
 Directory: devel
 
 Tags: 5.1-alpha, 5.1-rc, rc