Re-enable Datalad SSH tests on macOS

.github/workflows/build-macos.yaml

@@ -340,6 +340,20 @@ jobs:
           hdiutil detach /Volumes/git-annex/
           echo /Applications/git-annex.app/Contents/MacOS >> "$GITHUB_PATH"
 
+      - name: Set up SSH target
+        shell: bash
+        run: |
+          # coreutils provides a readlink that supports `-f`
+          brew install coreutils docker docker-machine
+          mkdir -p ~/.docker/machine/cache
+          wget -O ~/.docker/machine/cache/boot2docker.iso https://github.com/boot2docker/boot2docker/releases/download/v19.03.12/boot2docker.iso
+          docker-machine create --driver virtualbox default
+          eval "$(docker-machine env default)"
+          export PATH="/usr/local/opt/coreutils/libexec/gnubin:$PATH"
+          curl -fSsL \
+            https://raw.githubusercontent.com/datalad/datalad/master/tools/ci/prep-travis-forssh.sh \
+            | bash
+          echo DATALAD_TESTS_SSH=1 >> "$GITHUB_ENV"
 
       - name: Set up environment
         run: |

.github/workflows/build-ubuntu.yaml

@@ -349,7 +349,6 @@ jobs:
             | bash
           echo DATALAD_TESTS_SSH=1 >> "$GITHUB_ENV"
 
-
       - name: Set up environment
         run: |
           git config --global user.email "[email protected]"

.github/workflows/template/build-{{ostype}}.yaml.j2

@@ -511,25 +511,24 @@ jobs:
           {{step}}
           {% endfor %}
 
-    {% if ostype == "ubuntu" %}
-    {# TODO: return for macos! https://github.com/datalad/git-annex/issues/42
-      {% if ostype == "ubuntu"  or ostype == "macos" %} #}
+    {% if ostype == "ubuntu"  or ostype == "macos" %}
       - name: Set up SSH target
         shell: bash
         run: |
           {% if ostype == "macos" %}
           # coreutils provides a readlink that supports `-f`
           brew install coreutils docker docker-machine
-          docker-machine --github-api-token="${{ secrets.GITHUB_TOKEN }}" create --driver virtualbox default
+          mkdir -p ~/.docker/machine/cache
+          wget -O ~/.docker/machine/cache/boot2docker.iso https://github.com/boot2docker/boot2docker/releases/download/v19.03.12/boot2docker.iso
+          docker-machine create --driver virtualbox default
           eval "$(docker-machine env default)"
           export PATH="/usr/local/opt/coreutils/libexec/gnubin:$PATH"
           {% endif %}
           curl -fSsL \
             https://raw.githubusercontent.com/datalad/datalad/master/tools/ci/prep-travis-forssh.sh \
             | bash
           echo DATALAD_TESTS_SSH=1 >> "$GITHUB_ENV"
-
-   {% elif ostype == "windows" %}
+    {% elif ostype == "windows" %}
       - name: Define test host alias
         shell: cmd
         run: |