revert: latest dfx version for face-recognition example

Author: marc0olo

.github/workflows/rust-face-recognition-example.yaml

@@ -19,11 +19,12 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Provision Darwin
-        run: bash .github/workflows/provision-darwin.sh
+        run: DFX_VERSION="0.20.2-beta.0" bash .github/workflows/provision-darwin.sh
       - name: Remove networks.json
         run: rm -f ~/.config/dfx/networks.json
       - name: Rust Face Recognition Darwin
         run: |
+          dfxvm install 0.22.0-beta.0
           dfx start --background
           pushd rust/face-recognition
           npm install
@@ -34,11 +35,12 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Provision Linux
-        run: bash .github/workflows/provision-linux.sh
+        run: DFX_VERSION="0.20.2-beta.0" bash .github/workflows/provision-linux.sh
       - name: Remove networks.json
         run: rm -f ~/.config/dfx/networks.json
       - name: Rust Face Recognition Linux
         run: |
+          dfxvm install 0.22.0-beta.0
           dfx start --background
           pushd rust/face-recognition
           npm install