build: rename config.h source

The meson-generated config.h template was previously named as
'config.h.meson' to avoid collisions with the autotools-generated
'config.h.in'.  Switch the source template to '.in' to follow typical
file naming patterns now that autotools is removed.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ie59d429732ab704ff7670a5ab5d2f5d4c6f09d21
diff --git a/config.h.meson b/config.h.in
similarity index 100%
rename from config.h.meson
rename to config.h.in
diff --git a/meson.build b/meson.build
index 6e8d350..e0893a6 100644
--- a/meson.build
+++ b/meson.build
@@ -45,7 +45,7 @@
 )
 
 configure_file(
-    input: 'config.h.meson',
+    input: 'config.h.in',
     output: 'config.h',
     configuration: config_data
 )