Add changelog entry for 0.19.0 (#647)

I added some info about how to migrate gradually
Also fix the docker build for the tanka image. It is failing because the latest kustomize release is not actually kustomize, it's kyaml

CHANGELOG.md

@@ -1,5 +1,27 @@
 # Changelog
 
+## 0.19.0 (2021-11-22)
+
+### Notice
+
+The go.yaml library's version lock was removed. Sequence items in YAML generated from the `manifestYamlFromJson` native function will have a different indent level.
+
+If you are exporting manifests from multiple environments with `tk export` and you wish to do it gradually, you can do it using the `--selector` argument. Here's an example where environments have a `cluster` label:
+
+```console
+// Export the dev cluster with the new version
+tk-new export outputs-dir tanka-dir --merge --selector cluster=dev
+// Export other clusters with the old version
+tk export outputs-dir tanka-dir --merge --selector cluster!=dev
+```
+
+### Bug Fixes
+
+- **helm**: match `Add()` and `AddRepos()` and correct typos
+  **[#641](https://github.com/grafana/tanka/pull/641)** (**redradrat**)
+- **yaml**: Remove yaml.v3's version lock
+  **[#643](https://github.com/grafana/tanka/pull/643)**
+
 ## 0.18.2 (2021-10-14)
 
 ### Features

Dockerfile

@@ -29,7 +29,9 @@ RUN export TAG=$(curl --silent "https://api.github.com/repos/helm/helm/releases/
 FROM golang:alpine3.13 as kustomize
 WORKDIR /tmp/kustomize
 RUN apk add --no-cache jq curl
-RUN export TAG=$(curl --silent "https://api.github.com/repos/kubernetes-sigs/kustomize/releases/latest" | jq -r .tag_name) &&\
+# Get the latest version of kustomize
+# Releases are filtered by their name since the kustomize repository exposes multiple products in the releases
+RUN export TAG=$(curl --silent "https://api.github.com/repos/kubernetes-sigs/kustomize/releases" | jq -r '[ .[] | select(.name | startswith("kustomize")) ] | .[0].tag_name') &&\
     export VERSION_TAG=${TAG#*/} &&\
     export OS=$(go env GOOS) &&\
     export ARCH=$(go env GOARCH) &&\