build: Update meson version requirement to 0.54.0

Use of the meson 'fallback arg in dependency' feature was introduced
by the switch to external checkasm in 3a2a874.

.gitlab-ci.yml

@@ -11,7 +11,7 @@ stages:
         - amd64
 
 .debian-amd64-minimum:
-    image: registry.videolan.org/dav1d-debian-minimum:20250207200301
+    image: registry.videolan.org/dav1d-debian-minimum:20260422185248
     stage: build
     tags:
         - docker

README.md

@@ -81,7 +81,7 @@ The [VideoLAN Code of Conduct](https://wiki.videolan.org/CoC) applies to this pr
 # Compile
 ## General compilation steps
 
-1. Install [Meson](https://mesonbuild.com/) (0.49 or higher), [Ninja](https://ninja-build.org/), and, for x86\* targets, [nasm](https://nasm.us/) (2.14 or higher)
+1. Install [Meson](https://mesonbuild.com/) (0.54 or higher), [Ninja](https://ninja-build.org/), and, for x86\* targets, [nasm](https://nasm.us/) (2.14 or higher)
 2. Run `mkdir build && cd build` to create a build directory and enter it
 3. Run `meson setup ..` to configure meson, add `--default-library=static` if static linking is desired
 4. Run `ninja` to compile

meson.build

@@ -28,7 +28,7 @@ project('dav1d', ['c'],
                       'warning_level=2',
                       'buildtype=release',
                       'b_ndebug=if-release'],
-    meson_version: '>= 0.49.0')
+    meson_version: '>= 0.54.0')
 
 dav1d_src_root = meson.current_source_dir()
 cc = meson.get_compiler('c')