Fixed flag name in help (--project to --projects)

[i582]

Issue

Closes #1273.

Checklist

• I have updated CHANGELOG.md
• I have run all the tests locally and no test failure was reported
• I have run the linter, formatter and spellchecker
• I did not do unrelated and/or undiscussed refactorings

[novusnota]

Hold on, the -p, --project flag is correct since it denotes a name of the project to build and it can be specified multiple times to selectively build multiple projects.

The issue wasn't with the help text, but with the actual CLI flag — it's --projects now, but should be just like in the help, i.e. --project

[i582]

Hold on, the -p, --project flag is correct since it denotes a name of the project to build and it can be specified multiple times to selectively build multiple projects.

The issue wasn't with the help text, but with the actual CLI flag — it's --projects now, but should be just like in the help, i.e. --project

What about current users who use the current --projects flag? If we change it to --project, we break all code that depends on the --projects flag

[anton-trunov]

@novusnota since we allow specifying multiple projects, it's only logical to call it --projects (plural)