Add bashate

... to enforce consistent format and also catch potential issues.
Note that shell script is mainly used in devstack plugin atm.

Change-Id: I0b37f5d8fe6401b6e3509f128994c10bb00f7295

.pre-commit-config.yaml

@@ -28,3 +28,9 @@ repos:
     hooks:
       - id: pyupgrade
         args: [--py3-only]
+  - repo: https://github.com/openstack/bashate
+    rev: 2.1.1
+    hooks:
+      - id: bashate
+        args: ['-v', '-iE006']
+        exclude: '.tox/.*'