src/main: add more DOI formats to NormalizeDOIs

I saw some DOIs like "www.doi.org" in our repository recently.

Author: alanorth

src/main/java/io/github/ilri/cgspace/ctasks/NormalizeDOIs.java

@@ -86,9 +86,11 @@ private static String getNormalizedDOI(MetadataValue itemDOI) {
         newDOI = newDOI.replace("http://", "https://");
         // 4. Prefer doi.org to dx.doi.org
         newDOI = newDOI.replace("dx.doi.org", "doi.org");
-        // 5. Replace values like doi: 10.11648/j.jps.20140201.14
+        // 5. Prefer doi.org to www.doi.org
+        newDOI = newDOI.replace("www.doi.org", "doi.org");
+        // 6. Replace values like doi: 10.11648/j.jps.20140201.14
         newDOI = newDOI.replaceAll("^doi: 10\\.", "https://doi.org/10.");
-        // 6. Replace values like 10.3390/foods12010115
+        // 7. Replace values like 10.3390/foods12010115
         newDOI = newDOI.replaceAll("^10\\.", "https://doi.org/10.");
 
         return newDOI;