feat: diff on release flow

Also, don't commit unstaged files.

tests/integration/recipe_release.bats

@@ -84,3 +84,22 @@ setup(){
 
   _reset_recipe "$TEST_RECIPE"
 }
+
+@test "unknown files not committed" {
+  run $ABRA recipe upgrade "$TEST_RECIPE" --no-input --patch
+  assert_success
+
+  run bash -c 'echo "unstaged changes" >> "$ABRA_DIR/recipes/$TEST_RECIPE/foo"'
+  assert_success
+  assert_exists "$ABRA_DIR/recipes/$TEST_RECIPE/foo"
+
+  run $ABRA recipe release "$TEST_RECIPE" --no-input --patch
+  assert_success
+  assert_output --partial 'no -p/--publish passed, not publishing'
+
+  run git -C "$ABRA_DIR/recipes/$TEST_RECIPE" rm foo
+  assert_failure
+  assert_output --partial "fatal: pathspec 'foo' did not match any files"
+
+  _reset_recipe
+}