Add needed secrets to make deployment work

[ctrueden]

With fea104fa16540bdce61f4c98248582fc1db5b5aa, I migrated the build from the no-longer-functional Travis CI system over to GitHub Actions. However, this repository still needs the SciJava secrets added, or else it won't be able to deploy snapshots or releases to maven.scijava.org.

The easiest way to set up the secrets would be to move this repository to an organization such as saalfeldlab that already has them.

@axtimwalde Otherwise, you'll have to go into Settings and paste them in there. I might be able to do it if you give me admin access to the repository, but I'm not sure; I haven't done this with other personal-account-based repositories yet.

[axtimwalde]

Oops... @ctrueden I tried to release, but I guess this issue does not allow the releases to be deployed. Can you help?

[ctrueden]

Sure, I ran mvn release:perform locally (with my deployment credentials) to finish the release. So mpicbg 1.5.0 artifacts are present on maven.scijava.org now. If you want the CI to be successful at that in the future, we can add the credentials as described above; let me know if/how you want to proceed there.

[axtimwalde]

Thanks!