Correct parsing of zero length byte strings.

src/main/java/com/fasterxml/jackson/dataformat/cbor/CBORParser.java

@@ -2079,7 +2079,7 @@ protected byte[] _finishBytes(int len) throws IOException
         // First, simple: non-chunked
         if (len >= 0) {
             byte[] b = new byte[len];
-            if (_inputPtr >= _inputEnd) {
+            if (_inputPtr > _inputEnd) {
                 loadMoreGuaranteed();
             }
             int ptr = 0;

src/test/java/com/fasterxml/jackson/dataformat/cbor/ParserBinaryTest.java

@@ -20,6 +20,7 @@ public Bytes() { }
     private final ObjectMapper MAPPER = cborMapper();
 
     public void testSmallBinaryValues() throws Exception {
+        _testBinary(0);
         _testBinary(1);
         _testBinary(20);
         _testBinary(100);