Update docs to reflect new DOI option

Author: clelange

docs/cernopendata-client-go.md

@@ -11,9 +11,10 @@ files and complete records.
 ### Options
 
 ```
+  -d, --doi string      Digital Object Identifier
   -h, --help            help for cernopendata-client-go
       --no-expand       expand files indices
-  -r, --record string   record ID to list (required)
+  -r, --record string   record ID to list
   -s, --server string   CERN Open Data server to query (default "http://opendata.cern.ch")
 ```
 
@@ -22,4 +23,4 @@ files and complete records.
 * [cernopendata-client-go download](cernopendata-client-go_download.md)	 - Download files belonging to a record
 * [cernopendata-client-go list](cernopendata-client-go_list.md)	 - Get a list of data file locations of a record
 
-###### Auto generated by spf13/cobra on 1-Oct-2020
+###### Auto generated by spf13/cobra on 21-Oct-2021

docs/cernopendata-client-go_download.md

@@ -23,13 +23,14 @@ cernopendata-client-go download [flags]
 ### Options inherited from parent commands
 
 ```
+  -d, --doi string      Digital Object Identifier
       --no-expand       expand files indices
-  -r, --record string   record ID to list (required)
+  -r, --record string   record ID to list
   -s, --server string   CERN Open Data server to query (default "http://opendata.cern.ch")
 ```
 
 ### SEE ALSO
 
 * [cernopendata-client-go](cernopendata-client-go.md)	 - A commandline tool to interact with the CERN Open Data portal
 
-###### Auto generated by spf13/cobra on 1-Oct-2020
+###### Auto generated by spf13/cobra on 21-Oct-2021

docs/cernopendata-client-go_list.md

@@ -21,13 +21,14 @@ cernopendata-client-go list [flags]
 ### Options inherited from parent commands
 
 ```
+  -d, --doi string      Digital Object Identifier
       --no-expand       expand files indices
-  -r, --record string   record ID to list (required)
+  -r, --record string   record ID to list
   -s, --server string   CERN Open Data server to query (default "http://opendata.cern.ch")
 ```
 
 ### SEE ALSO
 
 * [cernopendata-client-go](cernopendata-client-go.md)	 - A commandline tool to interact with the CERN Open Data portal
 
-###### Auto generated by spf13/cobra on 1-Oct-2020
+###### Auto generated by spf13/cobra on 21-Oct-2021