Avoid using log.Fatal in pkg/*

[Zettat123]

Follow up #1705

Replace some log.Fatal with decodeNode in pkg/model/workflow.go.

[mergify]

@Zettat123 this pull request has failed checks 🛠

[codecov]

Codecov Report

Merging #1759 (41db532) into master (4989f44) will increase coverage by 1.16%.
The diff coverage is 65.07%.

@@            Coverage Diff             @@
##           master    #1759      +/-   ##
==========================================
+ Coverage   61.22%   62.38%   +1.16%     
==========================================
  Files          46       48       +2     
  Lines        7141     7569     +428     
==========================================
+ Hits         4372     4722     +350     
- Misses       2462     2518      +56     
- Partials      307      329      +22     

Impacted Files	Coverage Δ
pkg/common/outbound_ip.go	0.00% <0.00%> (ø)
pkg/container/docker_cli.go	82.23% <ø> (ø)
pkg/container/docker_logger.go	52.08% <ø> (ø)
pkg/container/docker_pull.go	33.33% <ø> (ø)
pkg/container/docker_run.go	13.58% <0.00%> (-0.01%)	⬇️
pkg/container/docker_volume.go	0.00% <ø> (ø)
pkg/container/file_collector.go	39.68% <0.00%> (+2.38%)	⬆️
pkg/container/host_environment.go	0.00% <0.00%> (ø)
...ontainer/linux_container_environment_extensions.go	23.07% <0.00%> (-1.25%)	⬇️
pkg/exprparser/functions.go	66.32% <0.00%> (-1.04%)	⬇️
... and 22 more

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