Add 'go vet' to the test suite

https://github.com/opencost/opencost/pull/2469 is the only blocker

Signed-off-by: Matt Ray <github@mattray.dev>

justfile

@@ -9,6 +9,7 @@ default:
 # Run unit tests
 test:
     {{commonenv}} go test ./... -coverprofile=coverage.out
+    {{commonenv}} go vet ./...
 
 # Compile a local binary
 build-local: