Add workflow to test byzer-lang chart on PR

[chncaesar]

Description

This pr introduces a work-flow to test Byzer-lang chart. The test process is as follows:

1. Install minikube helm kubectl chart-testing
2. Run chart-testing:
   2.1 Create a namespace and install byzer-lang, and wait for the installation.
   2.2 Run helm test byzer-lang , which runs the pod defined in byzer-lang/templates/tests.

Change Description

cp_write_values_yaml.py : customize values.yaml to make sure byzer-lang run in a resource-constraint minikube.
lint_and_test.yaml: The wrorkflow to auomatically run on each PR
byzer-lang/templates/tests/test-connection.yaml: The testing pod.

Test

The workflow log:

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 ✔︎ byzer-lang => (version: "0.1.9", path: "byzer-lang")
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All charts installed successfully