Deprecate Useragent

Author: keilw

moneta-convert/moneta-convert-imf/src/main/java/org/javamoney/moneta/convert/imf/IMFRemoteSearchCallable.java

@@ -35,12 +35,15 @@ class IMFRemoteSearchCallable implements Callable<IMFRemoteSearchResult>{
 
 	private final IMFHistoricalType type;
 	private final YearMonth yearMonth;
+
+	/** The Useragent
+	 * @deprecated not needed anymore for IMF, likely removed */
 	private final String userAgent;
 
 	IMFRemoteSearchCallable(IMFHistoricalType type, YearMonth yearMonth, String userAgent) {
 		this.type = Objects.requireNonNull(type);
 		this.yearMonth = Objects.requireNonNull(yearMonth);
-		this.userAgent = Objects.requireNonNull(userAgent);
+		this.userAgent = userAgent;
 	}