Could not resolve dependencies due to certification errors

We are using Artifactory to up- and download our build artefacts / dependencies. The Artifactory is only accessible via HTTPS and uses self signed certificates. When I try to download runtime dependencies with yaks I got the following error message:
```
14:50:31 + yaks run TollDeclaration.feature --settings yaks-config.yaml
14:50:31 Test 'toll-declaration' updated
14:50:36 [test-toll-declaration-cnpgtdrf9prc73bef9m0-bh4lr test-1] Monitoring pod test-toll-declaration-cnpgtdrf9prc73bef9m0-bh4lr
14:50:36 [test-toll-declaration-cnpgtdrf9prc73bef9m0-bh4lr test-1] [ERROR] Failed to execute goal on project yaks-runtime-maven: Could not resolve dependencies for project org.citrusframework.yaks:yaks-runtime-maven:jar:0.17.1: Failed to collect dependencies at org.foo:foo-artifact:jar:1.0.0: Failed to read artifact descriptor for org.foo:foo-artifact:jar:1.0.0: The following artifacts could not be resolved: org.foo:foo-artifact:pom:1.0.0 (absent): Could not transfer artifact org.foo:foo-artifact:pom:1.0.0 from/to myRepo (https://path-to-repository): PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target -> [Help 1]
14:50:36 [test-toll-declaration-cnpgtdrf9prc73bef9m0-bh4lr test-1] [ERROR]
14:50:36 [test-toll-declaration-cnpgtdrf9prc73bef9m0-bh4lr test-1] [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
14:50:36 [test-toll-declaration-cnpgtdrf9prc73bef9m0-bh4lr test-1] [ERROR] Re-run Maven using the -X switch to enable full debug logging.
14:50:36 [test-toll-declaration-cnpgtdrf9prc73bef9m0-bh4lr test-1] [ERROR]
14:50:36 [test-toll-declaration-cnpgtdrf9prc73bef9m0-bh4lr test-1] [ERROR] For more information about the errors and possible solutions, please read the following articles:
14:50:36 [test-toll-declaration-cnpgtdrf9prc73bef9m0-bh4lr test-1] [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException
```
How can I add the server certificate the test pods trust store?