Prepare the CHANGELOG for 0.8.0

[almet]

Updates the CHANGELOG file with all the changes since last release.

Closes #965

[apyrgio]

I have a few more notable changelog entries:

Fixed

• Make Dangerzone work on Linux systems with SELinux in enforcing mode (SELinux in enforcing mode breaks nested gVisor container #880)
• Process documents with embedded multimedia files without crashing (Make PyMuPDF always log to stderr #877)
• Search for applications that can read PDF files in a more reliable way (not starting, "not enough values to unpack" #899)
• Handle and report some stray conversion errors (Unhandled exceptions occurring inside function passed to executor.map are swallowed #776). Thanks @amnak613 for the contribution!
• Replace occurences of the word "Docker" in Podman-related error messages in Linux (Wrong container runtime detection on Linux #212)

Changed

• Disable the DirectFS feature of gVisor (Defense in Depth - SELinux #226). This makes gVisor work without the openat() system call, which is good from a security perspective, but comes with a small performance penalty. Thanks @EtiennePerot for the contribution!
• Debian packages are now amd64 only, which removes some warnings in Linux distros with 32-bit repos enabled (Notice when installing from packages.freedom.press #394)
• Allow choosing installation directory on Windows platforms (Windows installer: add option to change installation directory #148). Thanks @jkarasti for the contribution!
• Bumped H2ORestart LibreOffice extension to version 0.6.6 (Bump H2ORestart to version 0.6.6 #943)
• Development: Build Debian packages with pybuild (Replace stdeb with a different way to produce Debian packages #773)
• Development: Test Dangerzone on Intel macOS machines as well (Preparations for the on-host conversion PR #932)

[apyrgio]

Also, general question. Until 0.7.1, we linked to GitHub issues from our changelog entries, and if none existed, we then fell back to PRs. In the 0.8.0 section, I see that we link to PRs by default. Should we revert to the previous behavior, or change this rule?

In any case, maybe it's best to state our preference in RELEASE.md.

[almet]

Thanks for the proposed changes. I've updated both the script to get release notes and the changelog here to account with your remarks.

In addition to the inline comments, commit 28786fc updates the links to reference issues rather than PRs and regroup development changes together.

Also, general question. Until 0.7.1, we linked to GitHub issues from our changelog entries, and if none existed, we then fell back to PRs. In the 0.8.0 section, I see that we link to PRs by default. Should we revert to the previous behavior, or change this rule?

I don't have a preference, I just forgot this was the case. If you prefer issues then let's go with them!

[apyrgio]

Thanks a lot for the changes Alexis. Feel free to merge!

[almet]

I'll wait for the QA to be completed before merging, in case we have to introduce other fixes :-)