Fix Meson deprecation warning

CHANGELOG.md

@@ -18,6 +18,11 @@ Versioning](https://semver.org/spec/v2.0.0.html).
 - Fixed an obscure issue with VST3 plugins crashing in **Ardour** on
   Arch/Manjaro because of misreported parameter queue lengths.
 
+### Packaging notes
+
+- Fixed a deprecation warning in the Meson build, causing the minimum supported
+  Meson version to be bumped up to **Meson 0.56** from 0.55.
+
 ## [3.8.1] - 2022-03-08
 
 ### Changed

meson.build

@@ -2,7 +2,7 @@ project(
   'yabridge',
   'cpp',
   version : '3.8.1',
-  meson_version : '>=0.55',
+  meson_version : '>=0.56',
   default_options : [
     'warning_level=3',
     'cpp_std=c++2a',

src/common/config/meson.build

@@ -22,7 +22,7 @@ config_header = configure_file(
 #       directory, like when building the `yabridge` AUR package. In that case
 #       `vcs_tag()` should always fall back to the Meson project version.
 version_header = vcs_tag(
-  command : ['git', '--git-dir=' + (meson.source_root() / '.git'), 'describe', '--always'],
+  command : ['git', '--git-dir=' + (meson.project_source_root() / '.git'), 'describe', '--always'],
   input : 'version.h.in',
   output : 'version.h',
   replace_string : '@VCS_VERSION@'