v0.13.46: @newsroom.writer: the reader tests survive a slow apt mirror

Why. On 22 October the runners' Ubuntu mirror served the 26 MB of system packages Playwright's install-deps fetches at about 43 kB/s. The install step took 469 s, 612 s and 716 s instead of 24 to 41 s, and the reader-tests job hit its 12-minute limit mid-test in the runs for v0.13.44 and v0.13.45; v0.13.45 was never deployed.

• The packages are cached. The .deb files are kept between runs with actions/cache, handed to apt before install-deps, and saved after, so a slow mirror costs one run, not every run. apt retries a failed fetch three times.
• The limit is 25 minutes. Room for a cold cache on a slow mirror; a warm run should be back to about four minutes.
• What this release also carries. v0.13.45's update to application behaviour policies, with the PHP story site's compromise map.

Changed with the editor's approval: the workflow is in the second-key zone of the rules of the game.