Pin karma-rollup-preprocessor to 7.0.7 (#899)

Author: joshkel

package-lock.json

@@ -64,7 +64,7 @@
     "karma-firefox-launcher": "^2.1.3",
     "karma-jasmine": "^5.1.0",
     "karma-jasmine-html-reporter": "^2.1.0",
-    "karma-rollup-preprocessor": "^7.0.7",
+    "karma-rollup-preprocessor": "7.0.7",
     "karma-spec-reporter": "0.0.36",
     "ng-hammerjs": "^2.0.8",
     "pixelmatch": "^6.0.0",