Update x86.dockerfile

x86.dockerfile

 ## This file can be used to build x86 Linux, x86 Windows and Wasm versions of a Bevy project
 FROM r.lcr.gr/microhacks/msdfgen-builder:latest AS msdfgen
+FROM ghcr.io/rust-lang/rust:nightly-slim AS trunkbuild
+RUN cargo install --locked trunk && \
+    rm -rf ~/.cargo/registry/{cache,src}
+
+RUN which trunk
+
 FROM ghcr.io/rust-lang/rust:nightly-slim
 
 COPY --from=msdfgen /usr/bin/msdf-atlas-gen /usr/bin/msdf-atlas-gen