feat(contrib/util): add script to generate project contributors
docs(CHANGELOG): update for v0.13.0
chore(release): update version to v0.13.0
fix(deisctl): update `deisctl --version` string
Merge pull request #2087 from mboersma/fix-bump-version

fix(deisctl): update `deisctl --version` string
fix(README): update current version in badge
Merge pull request #2088 from mboersma/fix-bump-readme

fix(README): update current version in badge
Merge pull request #2077 from carmstrong/add_contributors_script

feat(contrib/util): add script to generate project contributors
ref(Makefile): refactor `make dev-release`

This allows us to run `make -C controller config` when we know that
the image is pushed onto the registry and we just need to tell the
cluster to use this image.
fix(registry): make deis-cache mandatory

Sometimes the redis cache would take longer than the registry to come
up. In that case, confd would then set the host and port to be "",
in which case the registry would parse the YAML value as `None`. This
change makes the cache mandatory in order for the registry to come up.
chore(deisctl): remove redundant CHANGELOG.md

These commits are now included in the root CHANGELOG.md.
Merge pull request #2091 from mboersma/remove-deisctl-changelog

chore(deisctl): remove redundant CHANGELOG.md
fix(registry): use YAML's nil type
docs(managing_deis): update controller_settings.

Controller has itself as a dependency. Remove it.
Merge pull request #2096 from chuenlye/docs-update-controller-settings

docs(managing_deis): update controller_settings.
support for multiple make discovery-url runs
fix(controller/tests): add fleet socket to controller tests
feat(registry): image without development libraries to reduce the size.
ref(logger): just use go. remove bash script.
fix(logger): the test is expecting the message "deis-logger running".