Fix CMakeLists.txt specifying a nonexistent pkgconfig package (#518)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index be552ac..ca612d1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -408,7 +408,7 @@
   DESCRIPTION "Brotli encoder library"
   VERSION "${BROTLI_VERSION_MAJOR}.${BROTLI_VERSION_MINOR}.${BROTLI_VERSION_REVISION}"
   URL "https://github.com/google/brotli"
-  DEPENDS_PRIVATE brotlicommon
+  DEPENDS_PRIVATE libbrotlicommon
   LIBRARIES brotlienc)
 
 if(NOT BROTLI_BUNDLED_MODE)