travis: reindent with 2 spaces by usual convention

Author: scop

.editorconfig

@@ -10,3 +10,6 @@ max_line_length = 79
 
 [Makefile.am]
 indent_style = tab
+
+[*.yml]
+indent_size = 2

.travis.yml

@@ -17,10 +17,10 @@ before_install:
 
 script:
   - docker run
-    -e CI=true -e DIST=$DIST -e BSD=$BSD
-    ${NETWORK:+--network $NETWORK}
-    -t bash-completion:$DIST test/docker/docker-script.sh
+      -e CI=true -e DIST=$DIST -e BSD=$BSD
+      ${NETWORK:+--network $NETWORK}
+      -t bash-completion:$DIST test/docker/docker-script.sh
   - if test $DIST = tools; then
-        test/run-shellcheck -f gcc bash_completion completions/!(Makefile*);
-        test/run-shellcheck -f gcc -s sh bash_completion.sh.in;
+      test/run-shellcheck -f gcc bash_completion completions/!(Makefile*);
+      test/run-shellcheck -f gcc -s sh bash_completion.sh.in;
     fi