Update downgrade dependency compat step

.github/workflows/CI.yml

@@ -9,7 +9,7 @@ on:
 
 jobs:
   test:
-    name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ matrix.num_threads }} threads - ${{ github.event_name }}
+    name: ${{ matrix.downgrade && 'Downgrade / ' || '' }}Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ matrix.num_threads }} threads - ${{ github.event_name }}
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
@@ -24,22 +24,24 @@ jobs:
         num_threads:
           - 1
           - 2
+        downgrade: [false]
+        include:
+          - version: '1.6'
+            os: ubuntu-latest
+            arch: x64
+            num_threads: 1
+            downgrade: true
     steps:
       - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v1
         with:
           version: ${{ matrix.version }}
           arch: ${{ matrix.arch }}
-      - uses: actions/cache@v4
-        env:
-          cache-name: cache-artifacts
+      - uses: julia-actions/cache@v1
+      - uses: julia-actions/julia-downgrade-compat@v1
         with:
-          path: ~/.julia/artifacts
-          key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ hashFiles('**/Project.toml') }}
-          restore-keys: |
-            ${{ runner.os }}-test-${{ env.cache-name }}-
-            ${{ runner.os }}-test-
-            ${{ runner.os }}-
+          skip: LinearAlgebra,Printf,Statistics
+        if: matrix.downgrade
       - uses: julia-actions/julia-buildpkg@latest
       - uses: julia-actions/julia-runtest@latest
         env:
@@ -49,27 +51,29 @@ jobs:
         with:
           file: lcov.info
   docs:
-    name: Documentation
+    name: ${{ matrix.downgrade && 'Downgrade / ' || '' }}Documentation - Julia ${{ matrix.version }}
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        include:
+          - version: '1'
+            downgrade: false
+          - version: '1.6'
+            downgrade: true
     steps:
       - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v1
         with:
           version: '1'
-      - run: |
-          julia --project=docs -e '
-            using Pkg
-            Pkg.develop(PackageSpec(path=pwd()))
-            Pkg.instantiate()'
-      - run: |
-          julia --project=docs -e '
-            using Documenter: DocMeta, doctest
-            using PSIS
-            DocMeta.setdocmeta!(PSIS, :DocTestSetup, :(using PSIS); recursive=true)
-            doctest(PSIS)'
-      - run: julia --project=docs docs/make.jl
+      - uses: julia-actions/cache@v1
+      - uses: julia-actions/[email protected]
+        with:
+          skip: LinearAlgebra,Printf,PSIS,Statistics
+          projects: ., docs
+        if: matrix.downgrade
+      - uses: julia-actions/julia-buildpkg@v1
+      - uses: julia-actions/julia-docdeploy@v1
         env:
-          JULIA_PKG_SERVER: ""
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          DOCUMENTER_KEY: ${{ secrets.DOCUMENTER_KEY }}
+          DOCUMENTER_KEY: ${{ matrix.version == '1' && secrets.DOCUMENTER_KEY || '' }}
           GKSwstype: "100" # https://discourse.julialang.org/t/generation-of-documentation-fails-qt-qpa-xcb-could-not-connect-to-display/60988