Update golangci-lint image to Go 1.14 to eliminate unnecessary warnings

Summary

This image: registry.gitlab.com/gitlab-org/gitlab-build-images:golangci-lint-alpine

This is recommended as the way to perform linting of Go projects in the Gitlab CI documentation, here: https://docs.gitlab.com/ee/development/go_guide/#automatic-linting

The problem is that the image is based on a Go version that does not include *testing.T Cleanup() (Go 1.13?) It should be updated to Go 1.14 to support current developer workflow.

Projects using *testing.T Cleanup() will have warnings generated during linting.

Improvements

Update the Go version in the image to Go 1.14

Optionally, provide multiple versions of the image with current releases of Go.

Risks

This seems pretty low risk given that all it is used for is linting code

Involved components

I think the image is the only component