Update ubuntu runner and remove special qemu stuff (#60)

* Update ubuntu runner and remove special qemu stuff
* Upgrade qemu and buildx to solve qemu segfault

.circleci/config.yml

@@ -31,10 +31,10 @@ workflows:
 jobs:
   build_and_test:
     environment:
-      - CI: "true"
-      - BUILDKIT_PROGRESS: plain
+      CI: "true"
+      BUILDKIT_PROGRESS: "plain"
     machine:
-      image: ubuntu-1604:202007-01
+      image: ubuntu-2004:202107-02
 
     steps:
       - checkout
@@ -46,10 +46,10 @@ jobs:
 
   release_build:
     environment:
-      - CI: "true"
-      - BUILDKIT_PROGRESS: plain
+      CI: "true"
+      BUILDKIT_PROGRESS: plain
     machine:
-      image: ubuntu-2004:202104-01
+      image: ubuntu-2004:202107-02
     steps:
     - checkout
     - run: ./.circleci/linux_circle_vm_setup.sh

.circleci/linux_circle_vm_setup.sh

@@ -3,23 +3,18 @@
 set -eu -o pipefail
 set -x
 
-sudo apt-get -qq update && sudo apt-get -qq install -y docker-ce-cli binfmt-support qemu-user-static
+# Get recent qemu to avoid constant qemu crashes on Ubuntu 20.04
+# Incomprehensible discussions of the problem at
+# https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1928075
+sudo add-apt-repository ppa:jacob/virtualisation
 
-BUILDX_BINARY_URL="https://github.com/docker/buildx/releases/download/v0.5.1/buildx-v0.5.1.linux-amd64"
+sudo apt-get -qq update && sudo apt-get -qq install -y docker-ce-cli binfmt-support  qemu qemu-user qemu-user-static
 
-curl --output docker-buildx \
-  --silent --show-error --location --fail --retry 3 \
-  "$BUILDX_BINARY_URL"
 
-mkdir -p ~/.docker/cli-plugins
-mv docker-buildx ~/.docker/cli-plugins
-chmod a+x ~/.docker/cli-plugins/docker-buildx
+# Get recent buildx
+mkdir -p ~/.docker/cli-plugins && curl -sSL -o ~/.docker/cli-plugins/docker-buildx https://github.com/docker/buildx/releases/download/v0.6.3/buildx-v0.6.3.linux-amd64 && chmod +x ~/.docker/cli-plugins/docker-buildx
 
-docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
-
-if ! docker buildx inspect ddev-builder-multi --bootstrap >/dev/null; then docker buildx create --name ddev-builder-multi; fi
-docker buildx use ddev-builder-multi
-docker buildx inspect --bootstrap
-
-which dpkg-split
+docker buildx version
 
+if ! docker buildx inspect ddev-builder-multi --bootstrap >/dev/null; then docker buildx create --name ddev-builder-multi --use; fi
+docker buildx inspect --bootstrap