add Downgrade workflow run

Author: lmiq

.github/workflows/Downgrade.yml

@@ -0,0 +1,29 @@
+name: Downgrade
+on:
+  pull_request:
+    branches:
+      - main
+    paths-ignore:
+      - 'docs/**'
+  push:
+    branches:
+      - main
+    paths-ignore:
+      - 'docs/**'
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        version:
+          - '1.9.0'
+    steps:
+      - uses: actions/checkout@v4
+      - uses: julia-actions/setup-julia@v1
+        with:
+          version: ${{ matrix.version }}
+      - uses: cjdoris/julia-downgrade-compat-action@v1
+        with:
+          skip: Pkg,TOML
+      - uses: julia-actions/julia-buildpkg@v1
+      - uses: julia-actions/julia-runtest@v1

Project.toml

@@ -30,12 +30,12 @@ CellListMap = "0.8.16"
 Chemfiles = "0.9, 0.10"
 ChunkSplitters = "2.1"
 DelimitedFiles = "1.9"
-DocStringExtensions = "0.8, 0.9"
-Documenter = "1"
+DocStringExtensions = "0.9"
+Documenter = "1.3"
 FortranFiles = "0.6"
 JSON3 = "1"
 LinearAlgebra = "1.9"
-PDBTools = "1.1"
+PDBTools = "1.2"
 PrecompileTools = "1"
 Printf = "1.9"
 ProgressMeter = "1.9"