How to get the latest Tomcat version?
Get the latest version of Tomcat:

$ curl -s 'https://api.github.com/repos/apache/tomcat/tags?per_page=1' | jq -r .[].name
9.0.20


Get the latest version of Tomcat 9:

$ curl -s 'https://api.github.com/repos/apache/tomcat/tags?per_page=100' | jq -r '.[] | .name' | sort -V | grep ^9 | tail -n 1
9.0.20


Get the latest version of Tomcat 8.5:

$ curl -s 'https://api.github.com/repos/apache/tomcat/tags?per_page=100' | jq -r '.[] | .name' | sort -V | grep ^8.5 | tail -n 1
8.5.41


Get the latest version of Tomcat 7:

$ curl -s 'https://api.github.com/repos/apache/tomcat/tags?per_page=100' | jq -r '.[] | .name' | sort -V | grep ^7 | tail -n 1
7.0.94


These all currently match the latest versions listed at http://tomcat.apache.org/