.github/workflows/config.yml: add --platform for qemu environment

Fixes
```
+ docker run --rm --platform linux/amd64 -v /home/runner/work/EusLisp/EusLisp:/ws/euslisp -e ARCH=LinuxARM -t arm32v7/debian:unstable-slim bash -c '      set -x; set -e;      apt update -qq;      apt install -y -qq make gcc libgl-dev libglu1-mesa-dev libjpeg-dev libpng-dev libpq-dev libx11-dev libxext-dev;      CFLAGS='\''-Werror=implicit-function-declaration'\'' ARCH=LinuxARM EUSDIR=/ws/euslisp make -C /ws/euslisp/lisp/ -f Makefile.LinuxARM eus0;      CC='\''gcc -Werror'\'' ARCHDIR=LinuxARM EUSDIR=/ws/euslisp make -C /ws/euslisp/lisp/image/jpeg;      exit 0'
Unable to find image 'arm32v7/debian:unstable-slim' locally
unstable-slim: Pulling from arm32v7/debian
docker: no matching manifest for linux/amd64 in the manifest list entries.
```

.github/workflows/config.yml

@@ -89,22 +89,28 @@ jobs:
           if [[ "$QEMU" != "" ]]; then docker run --rm --privileged multiarch/qemu-user-static:register --reset; fi
           if [[ "$DOCKER_IMAGE" == *"arm"* ]]; then sudo apt-get install -y -qq qemu-user-static; fi
           if [[ "$DOCKER_IMAGE" == *"arm"* ]]; then git clone http://github.com/euslisp/jskeus ${HOME}/jskeus; fi
+          if [[ "$QEMU" != "" ]]; export PLATFORM_OPTION="--platform linux/$QEMU"; fi
           echo "Testing branch $TRAVIS_BRANCH of $REPOSITORY_NAME on $QEMU_VOLUME"
-          docker run --rm $QEMU_VOLUME -v $HOME:$HOME -e "QEMU=$QEMU" -e "TRAVIS_OS_NAME=$TRAVIS_OS_NAME" -e "CI_SOURCE_PATH=$CI_SOURCE_PATH" -e "HOME=$HOME" -e "MAKEFLAGS=$MAKEFLAGS" -e "DOCKER_IMAGE=$DOCKER_IMAGE" -t $DOCKER_IMAGE sh -c "cd $CI_SOURCE_PATH; ./.travis.sh"
+          docker run $PLATFORM_OPTION --rm $QEMU_VOLUME -v $HOME:$HOME -e "QEMU=$QEMU" -e "TRAVIS_OS_NAME=$TRAVIS_OS_NAME" -e "CI_SOURCE_PATH=$CI_SOURCE_PATH" -e "HOME=$HOME" -e "MAKEFLAGS=$MAKEFLAGS" -e "DOCKER_IMAGE=$DOCKER_IMAGE" -t $DOCKER_IMAGE sh -c "cd $CI_SOURCE_PATH; ./.travis.sh"
 
   debian-unstable:
     strategy:
       matrix:
         include:
           - DOCKER_IMAGE: amd64/debian:unstable-slim
+            DOCKER_PLATFORM: amd64
             ARCH: Linux64
           - DOCKER_IMAGE: arm32v7/debian:unstable-slim
+            DOCKER_PLATFORM: arm
             ARCH: LinuxARM
           - DOCKER_IMAGE: arm64v8/debian:unstable-slim
+            DOCKER_PLATFORM: aarch64
             ARCH: LinuxARM
           - DOCKER_IMAGE: s390x/debian:unstable-slim
+            DOCKER_PLATFORM: s390x
             ARCH: Linux
           - DOCKER_IMAGE: riscv64/debian:unstable-slim
+            DOCKER_PLATFORM: riscv64
             ARCH: Linux
 
     runs-on: ubuntu-latest
@@ -125,7 +131,7 @@ jobs:
           # This step will execute the registering scripts
           sudo apt install -y -qq qemu binfmt-support qemu-user-static
           docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
-          docker run --rm -v $(pwd):/ws/euslisp -e "ARCH=$ARCH" -t "$DOCKER_IMAGE" \
+          docker run --rm --platform linux/${{matrix.DOCKER_PLATFORM}} $(pwd):/ws/euslisp -e "ARCH=$ARCH" -t "$DOCKER_IMAGE" \
             bash -c " \
                set -x; set -e; \
                apt update -qq; \