Re-add skip_cleanup key

Even though `travis lint` marks the key as deprecated, the actual
deploy of the build fails because:
`If you need build artifacts for deployment, set `deploy.skip_cleanup: true`
as they are currently still on dpl v1.0, I presume

.travis.yml

@@ -16,6 +16,7 @@ deploy:
       secure: 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
     file_glob: true
     file: target/DataShot*.jar
+    skip_cleanup: true
     name: "DataShot-$(date +'%Y%m%d')-beta"
     prerelease: true
     on:
@@ -26,6 +27,7 @@ deploy:
       secure: 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
     file_glob: true
     file: target/DataShot*.jar
+    skip_cleanup: true
     prerelease: false
     on:
       repo: BernhardWebstudio/DataShot_DesktopApp