Fixes missing space when converting srcset to use absolute URLs (#40)

* Fixes missing space when converting srcset to use absolute URLs

* Fix integration snapshot

Author: jasonbarry

src/snapshot.ts

@@ -126,7 +126,7 @@ function getAbsoluteSrcsetString(doc: Document, attributeValue: string) {
       }
       return '';
     })
-    .join(',');
+    .join(', ');
 
   return resultingSrcsetString;
 }

test/__snapshots__/integration.ts.snap

@@ -229,7 +229,7 @@ exports[`[html file]: with-relative-res.html 1`] = `
   <img src=\\"http://localhost:3030/a.jpg\\" alt=\\"\\" srcset=\\"\\" />
   <img src=\\"http://localhost:3030/a.jpg\\" alt=\\"\\" srcset=\\"http://localhost:3030/a.jpg\\" />
   <img src=\\"http://localhost:3030/a.jpg\\" alt=\\"\\" srcset=\\"http://exmple.com/a.jpg\\" />
-  <img src=\\"http://localhost:3030/a.jpg\\" alt=\\"\\" srcset=\\"http://localhost:3030/a.jpg 3x,http://localhost:3030/a.jpg 45x,http://localhost:3030/b.png\\" /></body></html>"
+  <img src=\\"http://localhost:3030/a.jpg\\" alt=\\"\\" srcset=\\"http://localhost:3030/a.jpg 3x, http://localhost:3030/a.jpg 45x, http://localhost:3030/b.png\\" /></body></html>"
 `;
 
 exports[`[html file]: with-script.html 1`] = `