Fix module directive in go.mod

[alfa-alex]

I use to install binaries like these via go get. This is impossible due to the following error:

go get: github.com/rogchap/wombat@none updating to
	github.com/rogchap/wombat@v0.5.0: parsing go.mod:
	module declares its path as: wombat
	        but was required as: github.com/rogchap/wombat

This is because the module directive in the go.mod file is written as:

module wombat

whereas it would correctly be:

module github.com/rogchap/wombat

Are there any reasons not to change the module directive?

[alfa-alex]

Now that go get is deprecated to be used for that purpose, let me point out that the problem also exists with go install:

go install github.com/rogchap/wombat@latest

go install: github.com/rogchap/wombat@latest: github.com/rogchap/wombat@v0.5.0: parsing go.mod:
	module declares its path as: wombat
	        but was required as: github.com/rogchap/wombat```