Update to alr 2.0 instead of nightly (#5)

.github/workflows/branch.yml

@@ -1,13 +1,15 @@
 name: Source branch
 on: [pull_request]
+env:
+  TARGET_HEAD: v1-next
 
 jobs:
   check_pr:
     runs-on: ubuntu-latest
     steps:
     - name: Check on proper branch
-      if: github.head_ref != 'v1-next'
+      if: github.head_ref != env.TARGET_HEAD
       uses: actions/github-script@v3
       with:
         script: |
-          core.setFailed(`PRs for latest-stable must come from v1-next, but branch is ${{ github.head_ref }}`)
+          core.setFailed(`PRs for latest-stable must come from ${{ env.TARGET_HEAD }}, but branch is ${{ github.head_ref }}`)

.github/workflows/selftest.yml

@@ -10,11 +10,11 @@ jobs:
 
     runs-on: ${{ matrix.os }}
 
-    steps:      
+    steps:
       - uses: alire-project/alr-install@v1-next
         with:
           crates: gprbuild
-          # This can be changed to a more lightweight crate (hello) 
+          # This can be changed to a more lightweight crate (hello)
           # once we can install indexed releases.
           cache: false # Don't use cache for testing
 

action.yml

@@ -40,11 +40,9 @@ runs:
 
     - name: Set up alr
       if: steps.find-alr.outputs.available != 'true'
-      uses: alire-project/setup-alire@v2
+      uses: alire-project/setup-alire@v3
       with:
         cache: ${{inputs.cache}}
-        version: nightly
-        toolchain: --disable-assistant
 
     - name: Prepare --force
       id: force