/updpkgsums: pass all workflow dispatch inputs as strings

When using a bare number as input, GitHub reacts with 422 as
`statusCode` and the `statusMessage` "Unprocessable Entity".

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

GitForWindowsHelper/slash-commands.js

@@ -124,7 +124,7 @@ module.exports = async (context, req) => {
                 'updpkgsums.yml',
                 'main', {
                     repo,
-                    'pr-number': issueNumber,
+                    'pr-number': '' + issueNumber,
                     actor: commenter
                 }
             );

__tests__/index.test.js

@@ -354,7 +354,7 @@ The workflow run [was started](dispatched-workflow-updpkgsums.yml).`,
     expect(mockGetInstallationAccessToken).toHaveBeenCalledTimes(1)
     expect(mockGitHubApiRequestAsApp).not.toHaveBeenCalled()
     expect(dispatchedWorkflows).toHaveLength(1)
-    expect(dispatchedWorkflows.map(e => e.payload.inputs['pr-number'])).toEqual([104])
+    expect(dispatchedWorkflows.map(e => e.payload.inputs['pr-number'])).toEqual(['104'])
     expect(mockGitHubApiRequest).toHaveBeenCalled()
     const comment = mockGitHubApiRequest.mock.calls[mockGitHubApiRequest.mock.calls.length - 1]
     expect(comment[3]).toEqual('/repos/git-for-windows/MINGW-packages/issues/comments/0')