Support fetching without the --progress option

Setting the `progress` option to false in the `with` section of the
workflow step will cause git fetch to run without `--progress`.

The motivation is to be able to suppress the noisy progress status
output which adds many hundreds of "remote: Counting objects: 85%
(386/453)" and similar lines in the workflow log.

This should be sufficient to resolve #894 and its older friends,
though the solution is different to the one proposed there because
it doesn't use the --quiet flag. IIUC git doesn't show the progress
status by default since the output is not a terminal, so that's why
removing the --progress option is all that's needed.

Adding the --quiet flag doesn't make a lot of difference once the
--progress flag is removed, and actually I think using --quiet would
suppress some other more useful output that would be better left
visible.

Signed-off-by: Simon Baird <sbaird@redhat.com>

src/git-source-provider.ts

@@ -157,6 +157,7 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
       filter?: string
       fetchDepth?: number
       fetchTags?: boolean
+      showProgress?: boolean
     } = {}
     if (settings.sparseCheckout) fetchOptions.filter = 'blob:none'
     if (settings.fetchDepth <= 0) {