build: bump version to 0.16.0-dev

Same as [1].

[1]: https://github.com/swaywm/sway/pull/6730

include/wlr/meson.build

@@ -1,4 +1,5 @@
-version_array = meson.project_version().split('.')
+version_base = meson.project_version().split('-')[0]
+version_array = version_base.split('.')
 version_data = configuration_data()
 version_data.set_quoted('WLR_VERSION_STR', meson.project_version())
 version_data.set('WLR_VERSION_MAJOR', version_array[0])

meson.build

@@ -1,7 +1,7 @@
 project(
 	'wlroots',
 	'c',
-	version: '0.16.0',
+	version: '0.16.0-dev',
 	license: 'MIT',
 	meson_version: '>=0.58.1',
 	default_options: [