Azure Function: avoid errors about context.done()

An Azure Function is supposed to either return a `Promise` or call
`context.done()`, otherwise the following error will be shown:

  [Error]   Error: Choose either to return a promise or call 'done'. Do
  not use both in your script. Learn more:
  https://go.microsoft.com/fwlink/?linkid=2097909

Since we do prefer to return a `Promise`, let's just skip the call to
`context.done()`.

To be sure, these error messages are only shown in the Azure Portal,
when a developer deigns to turn on and look at the logs. Anyway, this
_is_ an error, so let's do fix it.

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

Author: dscho

GitGitGadget/index.js

@@ -21,7 +21,6 @@ module.exports = async (context, req) => {
             status: 403,
             body: 'Not a valid GitHub webhook: ' + e,
         };
-        context.done();
         return;
     }
 
@@ -112,7 +111,6 @@ module.exports = async (context, req) => {
                 context.res = {
                     body: `Not a command: '${comment.body}'`,
                 };
-                context.done();
                 return;
             }
 
@@ -137,6 +135,4 @@ module.exports = async (context, req) => {
             body: `Caught an error: ${e.message || JSON.stringify(e, null, 2)}`,
         };
     }
-
-    context.done();
 };