Update dev/release/verify-release-candidate.sh

Co-authored-by: Sutou Kouhei <kou@cozmixng.org>

Author: lidavidm

dev/release/verify-release-candidate.sh

@@ -249,7 +249,7 @@ install_dotnet() {
   if command -v dotnet; then
     show_info "Found $(dotnet --version) at $(which dotnet)"
 
-    if dotnet --version | grep 8\.0 > /dev/null 2>&1; then
+    if dotnet --version | grep --quiet --fixed-string 8.0; then
         local csharp_bin=$(dirname $(which dotnet))
         show_info "Found C# at $(which csharp) (.NET $(dotnet --version))"
         DOTNET_ALREADY_INSTALLED=1