Update extension to use major.minor versioning scheme (#73)

This change is needed for mozilla-extensions/xpi-manifest#215

In Bug 1793925, Firefox Desktop started to emit warnings when an extension's version doesn't match the format specified in the MDN docs.

To comply with this format, we need to drop the patch version on the add on pipeline web extensions.

The pipeline will now generate versions as major.minor.date.time

package.json

@@ -1,6 +1,6 @@
 {
   "name": "dnssec-interference-study",
-  "version": "4.2.0",
+  "version": "4.2",
   "description": "DNSSEC Interference Study",
   "main": "web-ext-config.js",
   "private": true,

src/manifest.json

@@ -2,7 +2,7 @@
     "manifest_version": 2,
     "name": "DNSSEC Interference Study",
     "description": "Mozilla addon that measures rates of DNSSEC interference by middleboxes",
-    "version": "4.2.0",
+    "version": "4.2",
     "hidden": true,
 
     "applications": {