Key-value Concourse resource v1.4.0

Improvements

• Bump Golang, dependencies, base images, and also Ginkgo & test dependencies
• Improved examples in README (see #1), thanks @sibevin!
• Fixed pipeline for proper notifying tests successes of Pull Requests
• Added pipeline job for weekly dependency bump with tests and Slack notification

Usage

resource_types:
  - name: key-value
    type: registry-image
    source:
      repository: gstack/keyval-resource
      tag: "1.4.0"