ci(Travis): move upgrading pip to travis

Author: KaiSchwarz-cnic

.travis.yml

@@ -17,8 +17,10 @@ branches:
     - master
     - /^dependabot.*$/
 install:
+- travis_retry pip install --upgrade pip
+- pip -V
 - travis_retry pip install -r requirements.txt
-- pip install -e .
+- travis_retry pip install -e .
 script:
 - "./scripts/pep8check.sh"
 - "./scripts/coverage.sh"
@@ -29,4 +31,4 @@ jobs:
       script:
         - npm prune
         - npm i
-        - npx semantic-release
+        - npx semantic-release