v1.21.0
Updated Apache Tika to v1.21
For changes, see https://tika.apache.org/1.21/index.html
Add magic comment to freeze string literals
Drop support for Ruby 2.2
Add Ruby 2.6 to test matrix
Updated Apache Tika to v1.21
For changes, see https://tika.apache.org/1.21/index.html
Add magic comment to freeze string literals
Drop support for Ruby 2.2
Add Ruby 2.6 to test matrix