Exclude guardrail test file from TruffleHog secret scanning

The sensitive_data_test.go file contains dummy connection strings
(postgres://, mongodb://, amqp://) used as test fixtures for the data
leak guardrail. These trigger false positives in TruffleHog.

Signed-off-by: Bryan Frimin <bryan@getprobo.com>

.github/workflows/secrets.yaml

@@ -19,4 +19,4 @@ jobs:
           submodules: recursive
       - uses: "trufflesecurity/trufflehog@b78fbfd8eb982f4802e09a265fb2bc37b3040975" # main
         with:
-          extra_args: "--results=verified,unknown"
+          extra_args: "--results=verified,unknown --exclude-paths=.trufflehog.yml"

.trufflehog.yml

@@ -0,0 +1,2 @@
+exclude_paths:
+  - "pkg/agent/guardrail/sensitive_data_test.go"