compat downgrade and spelling

.github/workflows/ci.yml

@@ -21,6 +21,11 @@ jobs:
           - '2'
         arch:
           - x64
+        include:
+          - os: ubuntu-latest
+            arch: x64
+            version: '1.9'
+            threads: 2
     steps:
       - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v1
@@ -37,6 +42,10 @@ jobs:
             ${{ runner.os }}-test-${{ env.cache-name }}-
             ${{ runner.os }}-test-
             ${{ runner.os }}-
+      - uses: cjdoris/julia-downgrade-compat-action@v1
+        if: ${{ matrix.version == '1.9' }}
+        with:
+          skip: Pkg, Random, LinearAlgebra
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
         env:

.github/workflows/spelling.yml

@@ -0,0 +1,15 @@
+name: Spell Check
+
+on: [pull_request]
+
+jobs:
+  typos-check:
+    name: Spell Check with Typos
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Actions Repository
+        uses: actions/checkout@v4
+      - name: Check spelling
+        uses: crate-ci/typos@master
+        with:
+            config: .typos.toml

.typos.toml

@@ -0,0 +1,2 @@
+[default.extend-words]
+ket = "ket"