Drop codecov.io

- It now requires an API key and a login to view reports
- Instead, use 'mvn clean install site -P jacoco' to view JaCoCo HTML
reports

Author: garydgregory

.github/workflows/coverage.yml

@@ -44,7 +44,6 @@ Apache Commons Pool
 ===================
 
 [![GitHub Actions Status](https://github.com/apache/commons-pool/workflows/Java%20CI/badge.svg)](https://github.com/apache/commons-pool/actions)
-[![Coverage Status](https://codecov.io/gh/apache/commons-pool/branch/master/graph/badge.svg)](https://app.codecov.io/gh/apache/commons-pool)
 [![Maven Central](https://maven-badges.herokuapp.com/maven-central/org.apache.commons/commons-pool2/badge.svg?gav=true)](https://maven-badges.herokuapp.com/maven-central/org.apache.commons/commons-pool2/?gav=true)
 [![Javadocs](https://javadoc.io/badge/org.apache.commons/commons-pool2/2.12.0.svg)](https://javadoc.io/doc/org.apache.commons/commons-pool2/2.12.0)
 [![CodeQL](https://github.com/apache/commons-pool/workflows/CodeQL/badge.svg)](https://github.com/apache/commons-pool/actions/workflows/codeql-analysis.yml?query=workflow%3ACodeQL)