Add timout for .gitlab-ci.yml

This setting is added because some glitch in the Pipelines ate up all
the quota for runners available in Gitlab.

Pipelines with a problem:

- https://gitlab.com/xorcare/testing-go-code-with-postgres/-/pipelines/1447744357
- https://gitlab.com/xorcare/testing-go-code-with-postgres/-/pipelines/1447744822
- https://gitlab.com/xorcare/testing-go-code-with-postgres/-/pipelines/1447747291

Author: xorcare

.gitlab-ci.yml

@@ -3,6 +3,9 @@ image: golang:1.22
 stages:
   - test
 
+default:
+  timeout: 3m
+
 # Check that all packages are compiling.
 build:
   stage: test