Libva 2.18.0

• doc: Add build and install libva informatio in home page.
• fix: NULL check before calling strncmp.
• ci: add dependabot
• va: fix the codying style of CHECK_DISPLAY
• va: remove dummy isValid() hook
• x11: use LIBVA_DRI3_DISABLE in GetNumCandidates
• win: compat_win32: Add getenv wrapper for WIN32
• win(WSL): va_drm_utils: Map d3d12 gallium driver for Windows Subsytem for Linux
• fix: Add libva.def into distribution package
• x11: allow disabling DRI3 via LIBVA_DRI3_DISABLe env var
• ci: enable Werror across the build
• win: explicitly ignore CloseAdapter return value
• win: use wide string literal where needed
• win: Add vaDisplayIsValid to .def export list
• va: Always build with va-messaging API
• meson: docs: use libva_version over project_version()
• ci: add github pages workflow
• meson: docs: add encoder interface for av1
• va: add VAProfileH264High10
• fix: Remove reference to non-existent symbol
• va: va/sysdeps.h: remove Android section
• va: remove Android pre Jelly Bean workarounds
• va: remove unused drm_sarea.h include & ANDROID references in va_dricommon.h