use a text-based comparison in the go-generate workflow

.github/workflows/go-generate.sh

@@ -2,7 +2,14 @@
 
 set -e
 
-find . -type f -name "*.go" -exec shasum {} \; > checksums_before.txt
+DIR=$(pwd)
+TMP=$(mktemp -d)
+cd "$TMP"
+mkdir orig generated
+cp -r "$DIR" orig
+cp -r "$DIR" generated
+
+cd generated
 # delete all go-generated files generated (that adhere to the comment convention)
 grep --include \*.go -lrIZ "^// Code generated .* DO NOT EDIT\.$" . | xargs --null rm
 # delete all files generated by Genny
@@ -11,11 +18,7 @@ grep --include \*.go -lrIZ "This file was automatically generated by genny." . |
 grep --include \*.go -lrI "//go:generate genny" | xargs -L 1 go generate
 # now generate everything
 go generate ./...
-find . -type f -name "*.go" -exec shasum {} \; > checksums_after.txt
-DIFF=$(diff checksums_before.txt checksums_after.txt) || true
-echo "$DIFF"
-if [ -n "$DIFF" ]; then
-  exit 1
-else
-  echo "All generated files match."
-fi
+cd ..
+
+# don't compare fuzzing corpora
+diff --exclude=corpus -ruN orig generated