try to fix test on older version of openresty

Author: windmgc

.github/workflows/tests.yml

@@ -2,6 +2,9 @@ name: Test
 
 on: [push, pull_request]
 
+env:
+  LIBEXPAT_DOWNLOAD_URL: https://github.com/libexpat/libexpat/releases/download/R_2_5_0/expat-2.5.0.tar.gz
+
 jobs:
   lint:
     runs-on: ubuntu-latest
@@ -30,9 +33,21 @@ jobs:
     - uses: actions/checkout@v2
     - name: Install deps
       run: |
-        apk add --no-cache curl perl bash wget git perl-dev libarchive-tools nodejs jq expat-dev
+        apk add --no-cache curl perl bash wget git perl-dev libarchive-tools nodejs jq
         ln -s /usr/bin/bsdtar /usr/bin/tar
 
+    - name: Build libexpat
+      if: matrix.openresty_version == '1.17.8.2'
+      run: |
+        mkdir -p /tmp/expat
+        curl -Ls $LIBEXPAT_DOWNLOAD_URL | tar -xz --strip-components=1 -f - -C /tmp/expat
+        cd /tmp/expat && ./configure && make && make install
+
+    - name: Install libexpat from package manager
+      if: matrix.openresty_version == '1.19.9.1'
+      run: |
+        apk add --no-cache expat-dev
+
     - name: Cache
       uses: actions/cache@v2
       with: