make license allowlist matching case insensitive (google#672)

this just makes it easier for our users to use.

pkg/osvscanner/vulnerability_result.go

@@ -3,6 +3,7 @@ package osvscanner
 import (
 	"fmt"
 	"sort"
+	"strings"
 
 	"github.com/google/osv-scanner/internal/sourceanalysis"
 	"github.com/google/osv-scanner/pkg/grouper"
@@ -66,10 +67,10 @@ func buildVulnerabilityResults(
 			pkg.Licenses = licensesResp[i]
 			allowlist := make(map[string]bool)
 			for _, license := range licensesAllowlist {
-				allowlist[license] = true
+				allowlist[strings.ToLower(license)] = true
 			}
 			for _, license := range pkg.Licenses {
-				if !allowlist[string(license)] {
+				if !allowlist[strings.ToLower(string(license))] {
 					pkg.LicenseViolations = append(pkg.LicenseViolations, license)
 				}
 			}