Update CI workflows and OSV scan script for improved functionality

- Updated the 'checkout' action to version 4 for consistency across workflows.
- Added a 'Setup Go' step to initialize the Go environment using the latest action version.
- Modified the OSV scan script to generalize vulnerability reporting, removing specific severity checks for a broader output.

scripts/osv_scan.sh

@@ -23,20 +23,16 @@ VULNS=$(jq -r '
   .results[]? |
   .source as $src |
   .vulns[]? |
-  select(
-    (.database_specific.severity // "" | ascii_upcase | test("HIGH|CRITICAL")) or
-    (.severity[]?.score // "" | tostring | split("/")[0] | tonumber? // 0 | . >= 7.0)
-  ) |
   "\(.id) (source: \($src))"
 ' "$OSV_JSON")
 
 if [ -n "$VULNS" ]; then
-    echo "OSV scan found HIGH/CRITICAL vulnerabilities:"
+    echo "OSV scan found vulnerabilities:"
     echo "$VULNS" | while IFS= read -r line; do
         echo " - $line"
     done
     exit 1
 else
-    echo "OSV scan: no HIGH/CRITICAL vulnerabilities found."
+    echo "OSV scan: no vulnerabilities found."
 fi