Swicth back to macos-10 (#337)

Author: ruzickap

.github/workflows/build.yml

@@ -38,7 +38,7 @@ env:
 jobs:
   build-boxes:
     name: "*"
-    runs-on: macos-11
+    runs-on: macos-10.15
     strategy:
       fail-fast: false
       matrix:
@@ -127,6 +127,7 @@ jobs:
         run: |
           set -x
           [[ -f /usr/local/bin/2to3 ]] && rm /usr/local/bin/2to3
+          rm -rf /Users/runner/Library/Developer /Users/runner/Library/Android /Users/runner/hostedtoolcache /Users/runner/.dotnet
           brew update > /dev/null
           brew install bash coreutils gettext gnu-sed jq packer [email protected] hudochenkov/sshpass/sshpass vagrant
           MATRIX_STAGE="${{ matrix.stage }}"