fix(ci): download arch-specific macnotary package

Author: addaleax

.evergreen/sign-packaged-artifact.sh

@@ -16,12 +16,16 @@ fi
 ls -lh dist/
 
 if [ "$(uname)" == Darwin ]; then
+  notary_arch=amd64
+  if [ `uname -m` = arm64 ]; then
+    notary_arch=arm64
+  fi
   # https://wiki.corp.mongodb.com/display/BUILD/How+to+use+MacOS+notary+service
   # download macnotary client
-  curl -LO https://macos-notary-1628249594.s3.amazonaws.com/releases/client/latest/darwin_amd64.zip
-  unzip darwin_amd64.zip
-  chmod +x ./darwin_amd64/macnotary
-  ./darwin_amd64/macnotary -v
+  curl -LO https://macos-notary-1628249594.s3.amazonaws.com/releases/client/latest/darwin_${notary_arch}.zip
+  unzip darwin_${notary_arch}.zip
+  chmod +x ./darwin_${notary_arch}/macnotary
+  ./darwin_${notary_arch}/macnotary -v
 
   FILE=$(echo ./dist/*.zip)
   echo "notarizing $FILE ..."