fastnumbers: pin hypothesis to binary-only in test env

PyPI's newest hypothesis has no riscv64 wheel (6.156+ ships as a
maturin/Rust build); pip resolved the highest version across both
indexes and fell back to the sdist on cp314t, which fails building
for riscv64gc (rustup does not recognize the triple). Scope
PIP_ONLY_BINARY to hypothesis in CIBW_TEST_ENVIRONMENT so pip lands
on our registry's riscv64 wheel (6.165.10) instead.

Author: luhenry

.github/workflows/build-fastnumbers.yml

@@ -57,6 +57,10 @@ jobs:
           CIBW_MANYLINUX_RISCV64_IMAGE: ${{ env.MANYLINUX_RISCV64_IMAGE }}
           # numpy has no riscv64 wheel on public PyPI.
           CIBW_ENVIRONMENT: PIP_EXTRA_INDEX_URL=https://pypi.riseproject.dev/simple/
+          # PyPI's newest hypothesis has no riscv64 wheel (maturin sdist, needs Rust);
+          # pin to binary-only so pip resolves our registry's riscv64 wheel instead
+          # of the newer sdist-only release (gotcha 210).
+          CIBW_TEST_ENVIRONMENT: PIP_ONLY_BINARY=hypothesis
           CIBW_TEST_REQUIRES: pytest pytest-faulthandler hypothesis typing_extensions numpy
           CIBW_TEST_COMMAND: >-
             cd {project} &&