[issue32271] Re-added 'hashSchema()' as 'fingerprintSchema()'

The new version removes the lift json dependencies and switched from
SHA-516 to MD5 hashing, per the avro spec. See links below for more
information:

http://avro.apache.org/docs/1.7.7/spec.html#handshake
http://avro.apache.org/docs/1.7.7/spec.html#Schema+Fingerprints
https://avro.apache.org/docs/1.7.6/api/java/org/apache/avro/SchemaNormalization.html