scripts: use ephemeral gocache in check-each-commit

scripts/check-each-commit.sh

@@ -12,4 +12,13 @@ if [[ "$(git log --pretty="%H %D" | grep "^[0-9a-f]*.* $1")" = "" ]]; then
 	echo "It seems like the current checked-out commit is not based on $1"
 	exit 1
 fi
+
+# Keep build cache ephemeral for this run to avoid long-term disk growth.
+TMP_GOCACHE=$(mktemp -d -t lnd-check-commit-gocache.XXXXXX)
+cleanup() {
+	rm -rf "$TMP_GOCACHE"
+}
+trap cleanup EXIT
+export GOCACHE="$TMP_GOCACHE"
+
 git rebase --exec scripts/check-commit.sh $1