Out 5.6 container is to old. Lets focus on the others for now

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

.drone.yml

@@ -2,31 +2,6 @@ pipeline:
     clone:
         image: plugins/git
         depth: 1
-    qt-5.6:
-        image: nextcloudci/client-5.6:latest
-        commands:
-            # Install QtKeyChain
-            - /bin/bash -c "
-              source /opt/qt56/bin/qt56-env.sh &&
-              cd /tmp &&
-              git clone https://github.com/frankosterfeld/qtkeychain.git &&
-              cd qtkeychain &&
-              git checkout v0.8.0 &&
-              mkdir build &&
-              cd build &&
-              cmake ../ &&
-              make &&
-              make install"
-            # Build client
-            - /bin/bash -c "
-              source /opt/qt56/bin/qt56-env.sh &&
-              mkdir build &&
-              cd build &&
-              cmake -D NO_SHIBBOLETH=1 ../ &&
-              make"
-        when:
-            matrix:
-                TESTS: qt-5.6
     qt-5.7:
         image: nextcloudci/client-5.7:latest
         commands:
@@ -105,7 +80,6 @@ pipeline:
 
 matrix:
     include:
-        - TESTS: qt-5.6
         - TESTS: qt-5.7
         - TESTS: qt-5.8
         - TESTS: qt-5.9