Add basic README

This required dropping the `trailing-whitespace` hook for `pre-commit`
as it conflicted with the markdown formatting one since that one wants
to ensure even empty lines in an indented block are indented

.pre-commit-config.yaml

@@ -24,5 +24,4 @@ repos:
 -   repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v5.0.0
     hooks:
-    -   id: trailing-whitespace
     -   id: end-of-file-fixer

README.md

@@ -0,0 +1,20 @@
+# `change-go-pkgs`
+
+Get Go packages that changed between two Git versions, usage:
+
+    NAME:
+       changed-go-packages - Get the changed Go packages between two commits
+
+    USAGE:
+       changed-go-packages [global options] command [command options]
+
+    COMMANDS:
+       help, h  Shows a list of commands or help for one command
+
+    GLOBAL OPTIONS:
+       --from-ref value
+       --to-ref value
+       --repo-dir value   The Git repo to inspect (default: ".")
+       --mod-dir value    Path to the directory containing go.mod. Used to find local packages (default: ".")
+       --log-level value  The level to log at. Valid values are: debug, info, warn, error (default: WARN)
+       --help, -h         show help