Belatedly make pyarrow a required dependency.

This should have happened on DM-41113, but it's only checked when
running GitHub Actions on downstream middleware packages, and there
weren't any branches downstream on that ticket.

pyproject.toml

@@ -32,6 +32,7 @@ dependencies = [
     "lsst-daf-relation",
     "deprecated >= 1.2",
     "pydantic >=2,<3.0",
+    "pyarrow >= 0.16",
 ]
 
 dynamic = ["version"]
@@ -49,7 +50,6 @@ test = [
     "pytest-openfiles >= 0.5.0",
     "numpy >= 1.17",
     "matplotlib >= 3.0.3",
-    "pyarrow >= 0.16",
     "pandas >= 1.0",
 ]
 # Also expose the optional dependencies of lsst-resources as optional

requirements.txt

@@ -9,6 +9,7 @@ git+https://github.com/lsst/sphgeom@main#egg=lsst-sphgeom
 git+https://github.com/lsst/utils@main#egg=lsst-utils
 git+https://github.com/lsst/resources@main#egg=lsst-resources
 git+https://github.com/lsst/daf_relation@main#egg=lsst-daf-relation
+pyarrow >= 0.16
 # optional
 backoff >= 1.10
 boto3 >= 1.13
@@ -17,7 +18,6 @@ moto >= 1.3
 pandas >= 1.0
 numpy >= 1.17
 matplotlib >= 3.0.3
-pyarrow >= 0.16
 responses >= 0.12.0
 urllib3 >= 1.25.10
 fastapi