Adjust permissions in workflow to reduce warnings in TravisCI logs.

[ndp-opendap]

Our TravisCI builds violate our wide spread repository rule that commits to master must come through an approved pull request.

This happens when:

• TravisCI tries to tag the master branch of the current repository
• When TravisCI checkouts out the master branch of a downstream project, makes a small change, and then commits the change and pushes it to master.

This works, but it creates warnings in our Travis logs:

New snapshot of BES pushed. Triggering a OLFS build
libdap4-snapshot record: libdap4-3.21.1-332 2025-12-02T00:11:15+0000
bes_version: 3.21.1-875
time_now: 2025-12-18T15:00:00+0000
BES_SNAPSHOT: bes-3.21.1-875 2025-12-18T15:00:00+0000
Tagging bes with version: 3.21.1-875
remote: Bypassed rule violations for refs/tags/3.21.1-875:        
remote: 
remote: - Cannot create ref due to creations being restricted.        
remote: 
remote: - This branch must not contain merge commits.        
remote:   Found 1 violation:        
remote: 
remote:   0791ec48a2e6cc4369382d1e56bee4292498027b        
remote: 
To https://github.com/OPENDAP/bes.git
 * [new tag]             3.21.1-875 -> 3.21.1-875
Cloning into 'olfs'...
Already on 'master'
Your branch is up to date with 'origin/master'.
libdap4-3.21.1-332 2025-12-02T00:11:15+0000
bes-3.21.1-875 2025-12-18T15:00:00+0000 test-deploy
[master a287a4d] bes: Triggering OLFS build for snapshot production.\nBuild Version Matrix:\nlibdap4-3.21.1-332 2025-12-02T00:11:15+0000\nbes-3.21.1-875 2025-12-18T15:00:00+0000
 1 file changed, 1 insertion(+), 1 deletion(-)
remote: Bypassed rule violations for refs/heads/master:        
remote: 
remote: - Changes must be made through a pull request.        
remote: 
To https://github.com/OPENDAP/olfs.git
   6e1eb18..a287a4d  master -> master
travis_time:end:00e0efe8:start=1766070000956693377,finish=1766070010110548807,duration=9153855430,event=script
�[0K�[32;1mThe command "./travis/trigger-olfs-build.sh" exited with 0.�[0m

Is there a way in Gitlandia that we can fiddle this??