task: Sanitize git log output when building COMMIT variable

[ardnew]

This PR fixes a bug in Taskfile.yml.

If the user has configured git to always show commit signatures in git log, then task could emit malformed arguments to the go build command generated from task build.

For example, in my git config file:

[log]
  showSignature = true

And then running task build you will see rather confusing output:

arduino-cli $ task build
task: [build] go build -v -ldflags ' -X github.com/arduino/arduino-cli/version.versionString=git-snapshot -X github.com/arduino/arduino-cli/version.commit=gpg: Signature made Thu Jul  1 12:22:24 2021 CDT
gpg:                using RSA key 4AEE18F83AFDEB23
gpg: Can't check signature: No public key
1b055e5e -X github.com/arduino/arduino-cli/version.date=2021-07-01T22:25:11Z '

task: Failed to run task "build": 4:78: reached EOF without closing quote '

This PR adds an argument to suppress signature output from the offending git log command in Taskfile.yml.

Now running task build completes as expected:

arduino-cli $ task build
task: [build] go build -v -ldflags ' -X github.com/arduino/arduino-cli/version.versionString=git-snapshot -X github.com/arduino/arduino-cli/version.commit=892a2ba1 -X github.com/arduino/arduino-cli/version.date=2021-07-01T23:10:16Z '

arduino-cli $ ./arduino-cli version
arduino-cli alpha Version: git-snapshot Commit: 892a2ba1 Date: 2021-07-01T23:10:16Z

[CLAassistant]

All committers have signed the CLA.

[silvanocerza]

Nice catch! We surely never stumbled upon this but it's nonetheless a nice fix.
Thanks!

[silvanocerza]

Don't worry about the integration tests failing, they're kinda flaky when running on GH. 😕
I'll handle the merge when they're all green.