implemented #115: make parameter for site name not case sensitive

sherlock.py

@@ -369,10 +369,12 @@ def main():
         # Make sure that the sites are supported & build up pruned site database.
         site_data = {}
         site_missing = []
+        site = str()
         for site in args.site_list:
-            if site in site_data_all:
-                site_data[site] = site_data_all[site]
-            else:
+            for existing_site in site_data_all:
+                if site.lower() == existing_site.lower():
+                    site_data[existing_site] = site_data_all[existing_site]
+        if not site_data:
             # Build up list of sites not supported for future error message.
             site_missing.append(f"'{site}'")