No longer use mdbook-svgbob2

Author: tbfleming

docker/ubuntu-2004-builder.Dockerfile

@@ -74,9 +74,7 @@ RUN cd /root \
     && curl --proto '=https' --tlsv1.2 -sSf -o rustup.sh https://sh.rustup.rs \
     && chmod 700 rustup.sh \
     && ./rustup.sh -y --no-modify-path \
-    && /opt/cargo/bin/cargo install mdbook \
-    && /opt/cargo/bin/cargo install mdbook-svgbob2 \
-    && /opt/cargo/bin/cargo install sccache \
+    && /opt/cargo/bin/cargo install mdbook sccache \
     && chmod -R 777 $RUSTUP_HOME \
     && chmod -R 777 $CARGO_HOME \
     && rm rustup.sh