Retract versions v1.1.0 through v1.1.5 from Go modules

[zrhoffman]

This PR retracts v1.1.0, v1.1.1, v1.1.2, v1.1.3, v1.1.4, and v1.1.5-retractions from Go modules. If this PR is merged, it should be tagged version v1.1.5-retractions.

Without this PR and tag v1.1.5-retractions, a user running

go mod init my-module
go get github.com/apache/trafficcontrol@817a702a9de6

will retrieve dependency github.com/apache/trafficcontrol at version v1.1.4-0.20201118150121-817a702a9de6. With this PR merged and tagged v1.1.5-retractions, the same go get command will yield version v0.0.0-20201118150121-817a702a9de6.

---

Which Traffic Control components are affected by this PR?

• go.mod

What is the best way to verify this PR?

git clone https://github.com/apache/trafficcontrol
cd trafficcontrol
# create github.com:my-username/nonfork using the GitHub UI
git remote add nonfork git@github.com:my-username/nonfork.git
git push nonfork --all
git push nonfork --tags
sed -i 's|github\.com/apache/trafficcontrol|github.com/my-username/nonfork|' go.mod
git add go.mod
git commit -m 'Update module path to github.com/my-username/nonfork'
git push nonfork HEAD:master

In a different window, try getting a 4.1.x commit:

mkdir my-project
cd my-project
go mod init my-project
go get github.com/my-fork/nonfork@817a702a9d

Expected computed version: v1.1.4-0.20201118150121-817a702a9de6

Back in the first window, retract v1:

<<'APPEND' cat >> go.mod
// Although the Apache Traffic Control considers v7.0.1 stable, Go modules consider it unstable because its major version
// is greater than 1, and without these retractions, a commit like 817a702a9de6 will have a computed vesion of
// v1.1.4-0.20201118150121-817a702a9de6
// With these retractions, the same commit will have a computed version of
// v0.0.0-20201118150121-817a702a9de6
// See https://pkg.go.dev/cmd/go@go1.15.15#hdr-Module_compatibility_and_semantic_versioning for details.
retract (
	v1.1.5-retractions
	v1.1.4
	v1.1.3
	v1.1.2
	v1.1.1
	v1.1.0
)
APPEND
git add go.mod
git commit -m 'Retract v1'
git tag v1.1.5-retractions
git push nonfork HEAD:master v1.1.5-retractions

Back in the my-project window, try importing the 4.1.x commit again:

sudo rm -rf ${GOPATH}/pkg
go get github.com/my-username/nonfork@817a702a9de6

Expected computed version: v0.0.0-20201118150121-817a702a9de6

PR submission checklist

• This PR has tests
• This PR has comments
• This PR has a CHANGELOG.md entry
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

[zrhoffman]

We could also tag it something like v1.1.5-retractions, it doesn't need to be named only v1.1.5

[zrhoffman]

Rebased onto latest master

[zrhoffman]

Rebased to get the t3c test nonbreakage from #7198