Add support for specifying overrides in the command line for new projects

changes/1552.feature.rst

@@ -0,0 +1 @@
+When creating new projects with the ``briefcase new`` command, project configuration overrides can be specified via the ``-Q`` command line argument. For instance, a specific license can be specified with ``-Q "license=MIT license"``.

docs/reference/commands/new.rst

@@ -34,3 +34,18 @@ version of Briefcase that is being used (i.e., if you're using Briefcase 0.3.14,
 Briefcase will use the ``v0.3.14`` template branch when generating the app). If
 you're using a development version of Briefcase, Briefcase will use the ``main``
 branch of the template.
+
+``-Q <KEY=VALUE>``
+------------------
+
+Override the answer to a new project prompt with the provided value.
+
+For instance, if ``-Q "license=MIT license`` is specified, then the question to
+choose a license will not be presented to the user and the MIT license will be
+automatically used for the project. When used in conjunction with ``--no-input``,
+the provided value overrides the default answer.
+
+The expected keys are specified by the cookiecutter template being used to
+create the new project. Therefore, the set of possible keys is not listed here
+but should be expected to remain consistent for any specific version of
+Briefcase; with version changes, though, the keys may change.

src/briefcase/commands/dev.py

@@ -65,7 +65,7 @@ def add_options(self, parser):
             dest="run_app",
             action="store_false",
             default=True,
-            help="Do not run the app, just install requirements.",
+            help="Do not run the app, just install requirements",
         )
         parser.add_argument(
             "--test",