chore: updated maven to 3.8.7 in the superchain Dockerfile (#3898)

For some reason, 3.8.6 is no longer available on the Apache downloads website, but 3.8.7 is.

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[Apache 2.0 license]: https://www.apache.org/licenses/LICENSE-2.0

superchain/Dockerfile

@@ -39,7 +39,7 @@ RUN echo "deb http://deb.debian.org/debian buster-backports main" > /etc/apt/sou
 SHELL ["/bin/zsh", "-c"]
 
 # Prepare maven binary distribution
-ARG M2_VERSION="3.8.6"
+ARG M2_VERSION="3.8.7"
 ENV M2_DISTRO="https://www.apache.org/dist/maven/maven-3"
 RUN set -eo pipefail                                                                                                    \
   && curl -fSsL "${M2_DISTRO}/${M2_VERSION}/binaries/apache-maven-${M2_VERSION}-bin.tar.gz"                             \