Development dependency global installation workaround

[arcticicestudio]

The workaround implemented in #82 (PR #85) worked fine, but due to the explicitly disabled module mode it is not possible to define pinned dependency versions but only using the normal go get behavior to build the repositories default branch.

A better workaround is to run the go get command for development & build dependencies/packages outside of the project's root directory. Therefore the go.mod file is not in scope for the go get command and is therefore not updated. In order to use pinned versions the GO1111MODULE=on environment variable must be explicitly set when running the go get command.

See golang/go#30515 for more details and proposed solutions that might be added to Go's build tools in future versions.

[arcticicestudio]

Resolved in #89 (213111d)