This commit replaces `os.Setenv` with `t.Setenv` in tests. The
environment variable is automatically restored to its original value
when the test and all its subtests complete.
Reference: https://pkg.go.dev/testing#T.Setenv
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
It turned out that Helmfile has never had support for release template on `needs`.
This adds that, along with the new end-to-end test suite to verify helmfile template output with snapshot testing involving a real `helmfile build` command.
Ref #2098
Tsubasa Nagasawa
Yusuke Kuoka
yxxhero
Eng Zer Jun