Update hooks; Exclude markdown; Better pre-commit install command (#186)

* Update hooks; Exclude markdown; Better pre-commit install command

* Documented pre-commit more clearly

* Added warning about how pre-commit works

.pre-commit-config.yaml

@@ -9,9 +9,10 @@ repos:
           - .github/lint/.yamllint.yaml
         id: yamllint
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v4.0.1
+    rev: v4.1.0
     hooks:
       - id: trailing-whitespace
+        args: [--markdown-linebreak-ext=md]
       - id: end-of-file-fixer
       - id: mixed-line-ending
   - repo: https://github.com/Lucas-C/pre-commit-hooks
@@ -24,6 +25,6 @@ repos:
     hooks:
       - id: fix-smartquotes
   - repo: https://github.com/k8s-at-home/sops-pre-commit
-    rev: v2.0.3
+    rev: v2.1.0
     hooks:
       - id: forbid-secrets