feat: the update changelog covers every version you missed (#61)

Latest reads the last 10 releases in one request instead of only the
newest, so U and lazysecrets update --check show the changes of every
release since the running version, each under its version. Drafts and
pre-releases are skipped. A changelog taller than the screen is cut
with a pointer to the release pages.

Reviewed-on: #61

docs/config.md

@@ -151,7 +151,7 @@ published on GitHub and on git.kebcloud.no, and it asks them in that
 order, the next when one doesn't answer within 5 seconds;
 `updates.updateSources` lists others, such as a mirror of your own. Offline, or with
 every server down, it says nothing. A newer release shows in the footer, `v0.1.1 ↑ v0.2.0`; `U` (or
-`lazysecrets update --check`) shows its changelog.
+`lazysecrets update --check`) shows what changed since your version, across the last 10 releases.
 
 Updating (`u` there, or `lazysecrets update`) downloads the release for
 your OS and CPU from the first server that has it, checks it against