add diff Justfile recipe

Author: joshuadavidthomas

Justfile

@@ -9,6 +9,12 @@ mod project ".just/project.just"
 default:
     @just --list --list-submodules
 
+[private]
+diff SHA="HEAD":
+    #!/usr/bin/env bash
+    LATEST_TAG=$(git describe --tags --abbrev=0)
+    GIT_PAGER=cat git diff "$LATEST_TAG"..{{ SHA }} src/
+
 [private]
 fmt:
     @just --fmt