Fixed url in install.sh script

Old url (http://) returned http page with 301 status:

  <html>
  <head><title>301 Moved Permanently</title></head>
  <body>
  <center><h1>301 Moved Permanently</h1></center>
  <hr><center>nginx</center>
  </body>
  </html>

Url ws changed to https://.

Thank you so much to take time to contribute to the project.

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[ ] read the contribution guidelines
[ ] rebased your branch over master
[ ] verified that project is compiling and that tests pass: mvn -Prun-its clean install
[ ] marked as closed (in the commit comments) all issues ID that this PR should correct

jgitver / jgitver-maven-plugin

Fixed url in install.sh script #172