projects/neqo: Avoid ADD in Dockerfile (#13213)

CC @jonathanmetzman

Author: larseggert

projects/neqo/Dockerfile

@@ -16,9 +16,10 @@
 
 FROM gcr.io/oss-fuzz-base/base-builder-rust
 
-ADD https://github.com/nss-dev/nspr.git $SRC/nspr
-ADD https://github.com/nss-dev/nss.git $SRC/nss
-ADD https://github.com/mozilla/neqo.git $SRC/neqo
+RUN git clone --depth 1 https://github.com/nss-dev/nspr $SRC/nspr
+RUN git clone --depth 1 https://github.com/nss-dev/nss $SRC/nss
+RUN git clone --depth 1 https://github.com/mozilla/neqo $SRC/neqo
+RUN ls -l $SRC
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
         libclang-dev gyp ninja-build python-is-python3 zlib1g-dev \