Add read-all permissions and SPDX license headers in codeql.yml

The commit adds SPDX-FileCopyrightText and SPDX-License-Identifier headers at the top of codeql.yml, specifying a CC0-1.0 license for Winni Neessen's 2022 copyright. It also grants read-all permissions, ensuring all needed activities are allowed in the file's workflow.

.github/workflows/codeql.yml

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2022 Winni Neessen <winni@neessen.dev>
+#
+# SPDX-License-Identifier: CC0-1.0
+
 # For most projects, this workflow file will not need changing; you simply need
 # to commit it to your repository.
 #
@@ -19,6 +23,8 @@ on:
   schedule:
     - cron: '31 14 * * 1'
 
+permissions: read-all
+
 jobs:
   analyze:
     name: Analyze