fix(dockerfile): try to fix build errors (#7036) (#7037)

Co-authored-by: Lynwee <linwei.hou@merico.dev>
diff --git a/backend/Dockerfile b/backend/Dockerfile
index af5e73b..5a5e004 100644
--- a/backend/Dockerfile
+++ b/backend/Dockerfile
@@ -116,7 +116,7 @@
 FROM python:3.9-slim-bullseye as base
 
 RUN apt-get update && \
-    apt-get install -y python3-dev python3-pip tar curl libssh2-1 zlib1g libffi-dev default-libmysqlclient-dev libpq-dev tini && \
+    apt-get install -y python3-dev python3-pip tar pkg-config curl libssh2-1 zlib1g libffi-dev default-libmysqlclient-dev libpq-dev tini && \
     apt-get clean && \
     rm -fr /usr/share/doc/* \
            /usr/share/info/* \