Ensure that goroutines started by tests are cleaned up on termination.

Also:
* make TestLatencyHistories compatible with -count=X.
* Update to the supported versions of go 1.19 and 1.20.
* Update golangci-lint to v1.15.2

Fixes #641

Update testify to eliminate security issue in dependent package
gopkg.in/yaml.v3.

Fixes #652

Update GitHub actions to use the latest versions and add go mod
tidy check.

This bumps go version for tests to 1.20 and 1.21 the currently
supported versions.

Update checks to validate against Redis 7.2 and 7.0, removing 5.0 and
4.0 which may still work but haven't been updated since 2020.

Fix pubsub test instability due to unsubscribe notifications ordering
not being guaranteed.

Fix latency tests on Redis 7 due to DEBUG being disabled by default.

Run the Redis test server with --enable-debug-command local on Redis >= 7.0
which disables MODULE and DEBUG commands by default for better security.

Without this, some unit tests fail on later Redis versions.

Remove debug check now we run the test server with debug enabled if
needed.

Add TestOnBorrowContext to the Pool struct for checking the
health of the idle connection with a given context.

Add goreleaser to automate the generation of release notes and bump
the versions of github actions golang go the latest versions.

Remove deprecated goreleaser option --rm-dist and use --clean instead
to prevent deprecation warning.

Retract v1.8.10 which was tagged incorrectly for a feature release and
only available for a few minutes. v1.9.0 is identical.

Due to our test dependency requiring 1.17 minimum and the 1.16 being
well out of support, currently only 1.21 and 1.22 are support releases,
bump our required go version to 1.16.

Fixes #665

Move checkout before go-setup so caching works.