chore(release): bump version to 0.7.1

[basb7]

Bumps config/version.py to 0.7.1 ahead of the v0.7.1 release.

This is what every installation reports as flagward_version in telemetry, so it must match the tag before the release is cut.

v0.7.1 ships #69: the backend recognises OPENFEATURE_WEB (the @flagward/openfeature-web provider), and telemetry reports SDK types in a form the collector accepts.

How was it verified?

• pytest tests/unit/test_telemetry_version.py (the shipped version must be semver)
• End to end on a fresh database: an OPENFEATURE_WEB and a REACT registration → manage.py telemetry --show reports flagward_version: 0.7.1 and sdks[].type openfeature-web / react. That exact payload passes the collector's heartbeatV1 schema (flagward-telemetry/lib/schema/v1.ts); the same payload with openfeature_web is rejected on sdks.0.type.

Checklist

• ruff check . passes
• pytest passes (814)
• Commits follow Conventional Commits