lint: add script to check https violations

Rationale:
    During refactors/ports involving upstream, it's not unlikely that
    some headers will be directly taken from upstream without changing
    the protocol in the copyright header. This lint checks for cases
    like these.

test/lint/lint-copyright-https.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+#
+# Copyright (c) 2022 The Gridcoin developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://opensource.org/licenses/mit-license.php.
+
+export LC_ALL=C
+set -e
+
+if [[ -z "${COMMIT_RANGE}" ]]; then
+  echo "USAGE: COMMIT_RANGE=\"FIRST..LAST\" $0"
+  exit 0
+fi
+
+EXIT_CODE=0
+while read f; do
+  if grep -E "http://(www\.)?opensource.org" "$f" > /dev/null; then
+    EXIT_CODE=1
+    echo "$f: needs https correction for the copyright header."
+  fi
+done < <(git diff --name-only "${COMMIT_RANGE}")
+
+exit ${EXIT_CODE}
+