Remove buildtimetrend as public service has been discontinued

Signed-off-by: Michal Čihař <michal@cihar.com>

.travis.yml

@@ -79,10 +79,6 @@ cache:
     - $HOME/browserstack
     - $HOME/runkit
     - $HOME/.cache/pip
-# trigger Buildtime Trend Service to parse Travis CI log
-notifications:
-  webhooks:
-    - https://buildtimetrend.herokuapp.com/travis
 addons:
   apt:
     packages:

README.rst

@@ -22,10 +22,6 @@ Code status
 .. image:: https://scrutinizer-ci.com/g/phpmyadmin/phpmyadmin/badges/quality-score.png?s=93dfde29ffa5771d9c254b7ffb11c4e673315035
     :target: https://scrutinizer-ci.com/g/phpmyadmin/phpmyadmin/
 
-.. image:: https://buildtimetrend.herokuapp.com/badge/phpmyadmin/phpmyadmin
-    :alt: Buildtime Trend badge
-    :target: https://buildtimetrend.herokuapp.com/dashboard/phpmyadmin/phpmyadmin
-
 .. image:: https://bestpractices.coreinfrastructure.org/projects/213/badge
     :alt: CII Best Practices
     :target: https://bestpractices.coreinfrastructure.org/projects/213