This is because of the version discrepancy.
please update the version of your project that matches to your SDK version.
If you still face the error, re create the project with archetype command and make sure you mention the right version (not latest, be it in respective with the SDK version you have).
I have added dependencies associated with com.akamai.edgergrid.singer
com.akamai.edgergrid.singer.apachehttpclient in parent pom.xml as shown below and initiated build and build was successful.
I have created this demo project with maven archetype 26 and using AEM 6.5.9.
Could you please give a try to build your project from IDE(eclipse) and check.
In AEM default start level of bundle is 20. I don't think you have made any change at bundle start level.