ci: don't add --recursive when updating submodules

It's not generally needed. It was added in
https://github.com/tinygo-org/tinygo/pull/3958 to fix an issue with
binaryen that has since been fixed in a different way, so we don't need
the googletest dependency anymore.

Dockerfile

@@ -27,7 +27,7 @@ COPY . /tinygo
 
 # build the compiler and tools
 RUN cd /tinygo/ && \
-    git submodule update --init --recursive && \
+    git submodule update --init && \
     make gen-device -j4 && \
     make build/release