ci: Disallow npm dependencies from git

See:
https://github.blog/changelog/2026-02-18-npm-bulk-trusted-publishing-config-and-script-security-now-generally-available/#:~:text=New%20%2D%2Dallow%2Dgit%20flag,explicit%20control%20over%20this%20behavior.

Author: RandomByte

.npmrc

@@ -2,3 +2,4 @@
 registry=https://registry.npmjs.org/
 lockfile-version=3
 ignore-scripts=true
+allow-git=none