Merge pull request #6918 from brendandahl/v1.4

Bump version to 1.4

pdfjs.config

 {
   "betaVersion": "1.3.88",
   "stableVersion": "1.2.109",
-  "baseVersion": "194994a2898a6d01c434d6d3270357799f3ac820",
-  "versionPrefix": "1.3."
+  "baseVersion": "1eea0db897196417609ea3223fc9bd9728ed68ed",
+  "versionPrefix": "1.4."
 }
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