[calls] plugins: Fix install directory typo

[Evangelos Ribeiro Tzaras <devrtz src gnome org>]

commit 0e271226dc7f26fd66850fb84aa8573d52be1583
Author: Evangelos Ribeiro Tzaras <devrtz fortysixandtwo eu>
Date:   Wed Aug 24 21:21:08 2022 +0200

    plugins: Fix install directory typo
    
    Plugins could no longer be found because we installed the plugins
    outside the search path:
    The directory structure uses singular 'provider', not plural
    'providers'.
    
    Fixes 11ba83c16e827984ab1b14f29bd23ccd6e008ee2

 plugins/meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/plugins/meson.build b/plugins/meson.build
index bb89607c..d7a8e69d 100644
--- a/plugins/meson.build
+++ b/plugins/meson.build
@@ -1,4 +1,4 @@
-calls_provider_plugin_libdir = join_paths(full_calls_plugin_libdir, 'providers')
+calls_provider_plugin_libdir = join_paths(full_calls_plugin_libdir, 'provider')
 subdir('provider/mm')
 subdir('provider/dummy')
 subdir('provider/ofono')