Run test workflows only on specific paths (#8)

Author: orionmiz

.github/workflows/cargo.yml

@@ -1,8 +1,20 @@
 name: Cargo
 
 on:
-  - push
-  - pull_request
+  push:
+    paths:
+      - 'src/**'
+      - 'tests/**'
+      - '.cargo/**'
+      - 'Cargo.*'
+      - '.github/workflows/**'
+  pull_request:
+    paths:
+      - 'src/**'
+      - 'tests/**'
+      - '.cargo/**'
+      - 'Cargo.*'
+      - '.github/workflows/**'
 
 env:
   RUST_LOG: debug