Fix repo gate protection

[6543]

• clarify docs
• don't block cron pipelines
• run manual triggered pipelines right away

close #1340

[woodpecker-bot]

Deployment of preview was successful: https://woodpecker-ci-woodpecker-pr-1969.surge.sh

[codecov-commenter]

Codecov Report

Patch coverage: 45.37% and project coverage change: -0.24 ⚠️

Comparison is base (6c58e9d) 39.28% compared to head (88b2992) 39.05%.

❗ Your organization is not using the GitHub App Integration. As a result you may experience degraded service beginning May 15th. Please install the Github App Integration for your organization. Read more.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1969      +/-   ##
==========================================
- Coverage   39.28%   39.05%   -0.24%     
==========================================
  Files         177      179       +2     
  Lines       10734    10793      +59     
==========================================
- Hits         4217     4215       -2     
- Misses       6223     6282      +59     
- Partials      294      296       +2     

Impacted Files	Coverage Δ
pipeline/backend/docker/convert.go	8.46% <0.00%> (-0.14%)	⬇️
pipeline/backend/docker/docker.go	0.00% <0.00%> (ø)
pipeline/backend/kubernetes/pod.go	0.00% <0.00%> (ø)
pipeline/frontend/yaml/compiler/convert.go	0.00% <0.00%> (ø)
pipeline/frontend/yaml/types/container.go	77.77% <0.00%> (ø)
server/model/pipeline.go	0.00% <ø> (ø)
server/model/step.go	0.00% <ø> (ø)
server/model/workflow.go	0.00% <ø> (ø)
server/pipeline/create.go	0.00% <0.00%> (ø)
server/pipeline/gated.go	0.00% <0.00%> (ø)
... and 5 more

... and 2 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.