Get stdgems JSON files only if modified [ci skip]

.github/workflows/bundled_gems.yml

@@ -37,8 +37,10 @@ jobs:
 
       - name: Download previous gems list
         run: |
-          curl -o .downloaded-cache/bundled_gems.json https://stdgems.org/bundled_gems.json
-          ln -s .downloaded-cache/bundled_gems.json .
+          data=bundled_gems.json
+          mkdir -p .downloaded-cache
+          ln -s .downloaded-cache/$data .
+          curl -O -R -z ./$data https://stdgems.org/$data
 
       - name: Update bundled gems list
         run: |

.github/workflows/check_misc.yml

@@ -30,9 +30,10 @@ jobs:
 
       - name: Download previous gems list
         run: |
+          data=default_gems.json
           mkdir -p .downloaded-cache
-          curl -o .downloaded-cache/default_gems.json https://stdgems.org/default_gems.json
-          ln -s .downloaded-cache/default_gems.json .
+          ln -s .downloaded-cache/$data .
+          curl -O -R -z ./$data https://stdgems.org/$data
 
       - name: Make default gems list
         run: |