meson: Add pkg-config file (#310)

meson.build

@@ -6,6 +6,7 @@ project(
   meson_version: '>=0.56'
 )
 
+pkgc = import('pkgconfig')
 
 inja_dep = declare_dependency(
   include_directories: include_directories('include', 'third_party/include')
@@ -29,6 +30,15 @@ install_headers(
   subdir: 'inja'
 )
 
+pkgc.generate(
+    version: meson.project_version(),
+    name: 'inja',
+    description: 'Template engine for modern C++',
+    url: 'https://github.com/pantor/inja',
+    requires: ['nlohmann_json'],
+    dataonly: true,
+)
+
 
 run_command(
   find_program('scripts/update_single_include.sh'),