How can we move .github/workflows/ci.yaml back to synthtool's template?

As synthtool's template does not call `.kokoro/install_dependencies.sh `, I had to exclude ci.yaml from synthtool's management: https://github.com/googleapis/google-api-java-client/pull/1699/files#diff-c881f5091bb23fef16e6e6da031e4268bbb11bb3404c1a2c7da8afa53c26f4ecL32.

# What's missing in synthtool's template

## install_dependencies is not called.

How about the following options?

- build.sh to call install_dependencies.sh if it exists
- GitHub actions (ci.yaml) to call install_dependencies.sh if it exists

Does install_dependencies.sh work in Windows?

## Synthtool's template is missing to disable CRLF conversion.

```
- name: git configuration to avoid automatic CRLF conversion
run: |
git config --global core.autocrlf false
git config --global core.eol lf
```