Release v1.2.1

Functionality fixes

• Fix: Replace obsolete registerv-make with cl-defstruct #333
  • The registerv-make function was removed in Emacs 30. This change updates pdf-tools to use the modern cl-defstruct approach for register support, ensuring compatibility w
    ith Emacs 30+.
• Fix: Use correct key function for filtering page links in pdf-virtual #327
  • Fixes an issue where virtual PDF page links were not filtered correctly.

Native compilation fixes

• Fix: Resolve all native-comp warnings across multiple files #333
  • Added declare-function declarations to pdf-cache, pdf-info, pdf-util, and pdf-view to eliminate byte-compilation and native-comp warnings.
  • Fixed docstring formatting issues that caused native-comp warnings.

Installation and platform compatibility improvements

• Add doas as privilege escalation fallback in autobuild #323
  • The autobuild script now supports doas (used on Alpine Linux and OpenBSD) as an alternative to sudo for installing dependencies.

Infrastructure

• Move CI from CircleCI/AppVeyor to GitHub Actions
  • All testing now runs on GitHub Actions with a unified workflow for Ubuntu, macOS, and Windows.
  • Pre-built Windows binaries are now available as artifacts from CI runs.