chore: handle case where patch major doesn't exists

.github/workflows/update-expected.yml

@@ -42,8 +42,16 @@ jobs:
                     os=$(echo $patchName | grep -oP 'node-v[0-9.]+-(.*)-' | cut -d'-' -f3)
                     arch=$(echo $patchName | grep -oP 'node-v[0-9.]+-(.*)-(.*)' | cut -d'-' -f4)
 
-                    # replace in shas.txt file the sha matching the same major, os and arch
-                    sed -i -E "/$major[0-9.]+.-$os-$arch/c $sha $patchName" shas.txt
+                    if grep -E -q "$major[0-9.]+.-$os-$arch" shas.txt; then
+                        sed -i -E "/$major[0-9.]+.-$os-$arch/c $sha $patchName" shas.txt
+                    else
+                        # if file doesn't end with a newline, add it
+                        if [ "$(tail -c 1 shas.txt)" != "" ]; then
+                            echo "" >> shas.txt
+                        fi
+                        echo "$sha $patchName" >> shas.txt
+
+                    fi
                 done
             
             - name: Update expected shas