Unpin beam version and use default beam container images

Requires that we explicitly specify *everything*
required by our pipelines in requirements.txt, but means
we no longer have to maintain a complex image here. The
complex image also leads to complex hard to debug problems,
like #90 (comment)

pangeo_forge_runner/commands/bake.py

@@ -98,12 +98,14 @@ def _validate_job_name(self, proposal):
         return proposal.value
 
     container_image = Unicode(
-        # Provides apache_beam 2.48, which we pin to in setup.py
-        "quay.io/pangeo/forge:554675c",
+        "",
         config=True,
         help="""
         Container image to use for this job.
 
+        Defaults to letting beam automatically figure out the image to use,
+        based on version of beam and python in use.
+
         Should be accessible to whatever Beam runner is being used.
 
         Note that some runners (like the local one) may not support this!

setup.py

@@ -19,7 +19,7 @@
         "pangeo-forge-recipes>=0.9.2",
         "escapism",
         "traitlets",
-        "apache-beam[gcp]==2.48.0",
+        "apache-beam[gcp]",
     ],
     entry_points={
         "console_scripts": ["pangeo-forge-runner=pangeo_forge_runner.cli:main"]

tests/integration/test_dataflow_integration.py

@@ -12,7 +12,7 @@
 def test_dataflow_integration():
     pfr_version = parse_version(version("pangeo-forge-recipes"))
     if pfr_version >= parse_version("0.10"):
-        recipe_version_ref = "0.10.x"
+        recipe_version_ref = "beam-bump"
     else:
         recipe_version_ref = "0.9.x"
     bucket = "gs://pangeo-forge-runner-ci-testing"