Please support reading from stdin

[guettli]

Expected Behavior

Expected: This should print the current value of $HOME on stdout:

echo "\${HOME}" |  go run github.com/kreuzwerker/envplate/bin@latest

Expected: This should fail:

echo "\${var-does-not-exist}" |  go run github.com/kreuzwerker/envplate/bin@latest -s

Actual Behavior

Up to not the code does not read from stdin

Your Environment

• OS: Ubuntu 22.04
• envplate version: latest

Related tools

This tool reads from stdin, but has no strict mode: https://github.com/drone/envsubst

This tools supports reading from stdin and has a strict-mode via -u: https://github.com/icy/genvsub