ci: simplify main test workflow triggers to fire on any *.rs file change

Author: radhermit

.github/workflows/ci.yml

@@ -5,9 +5,7 @@ on:
     branches: ['**']
     paths:
       - "Cargo.*"
-      - "crates/*/build.rs"
-      - "crates/*/src/**"
-      - "crates/*/tests/**"
+      - "**/*.rs"
       - "crates/*/testdata/**"
       - ".github/workflows/ci.yml"
   pull_request: