Update bash

Changes:

- https://github.com/tianon/docker-bash/commit/e8084df: Update to commit cb7e76d009ff919138fa34413249b84eb1ce80cb
- https://github.com/tianon/docker-bash/commit/e22900d: Update to commit 560f608dd5459128f2165fa8bbd8c481eede1b42

library/bash

@@ -3,9 +3,9 @@
 Maintainers: Tianon Gravi <[email protected]> (@tianon)
 GitRepo: https://github.com/tianon/docker-bash.git
 
-Tags: devel-20200720, devel
+Tags: devel-20200731, devel
 Architectures: amd64, arm32v6, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: d8b5a2e5fa66c834dc6d2262c4928cc16dacca3e
+GitCommit: e8084dff964ec6f49c5205cd4f48e613f540be7a
 Directory: devel
 
 Tags: 5.1-alpha, 5.1-rc, rc