update travis examples

- use python 3.7 (requires xenial)
- remove --PR parameter for single addon repos: would only enables checking for a strictly higher version
- set git core.quotepath to false: fixes the addon filter for PRs, if utf-8 characters are used in file names
- combine into one command: fixes travisbuddy posting the same output two times

.travis-addon.example.yml

@@ -1,10 +1,10 @@
+dist: xenial
 language: python
-python:
-  - "3.6"
+python: 3.7
 
 install:
   - pip install kodi-addon-checker
 
 # command to run our tests
 script:
-  - kodi-addon-checker . --branch=BRANCH_NAME --PR
+  - kodi-addon-checker . --branch=BRANCH_NAME

.travis-repo.example.yml

@@ -1,14 +1,16 @@
+dist: xenial
 language: python
-python:
-  - "3.6"
+python: 3.7
 
 install:
   - pip install kodi-addon-checker
 
+before_script:
+- git config core.quotepath false
+
 # command to run our tests
 script:
-  - 'if [ "$TRAVIS_PULL_REQUEST" = "false" ]; then kodi-addon-checker --branch=BRANCH_NAME; fi'
-  - 'if [ "$TRAVIS_PULL_REQUEST" != "false" ]; then kodi-addon-checker --branch=BRANCH_NAME --PR $(git diff --diff-filter=d --name-only HEAD~ | grep / | cut -d / -f1 | sort | uniq); fi'
+  - kodi-addon-checker --branch=BRANCH_NAME $([ "$TRAVIS_PULL_REQUEST" != "false" ] && echo --PR $(git diff --diff-filter=d --name-only HEAD~ | grep / | cut -d / -f1 | sort | uniq))
 
 notifications:
   email: