Upgrade fmt dependency to v10.2.1 (#6869)

* Put fmt into version agnostic subdir

* Add fmt to dependency update script

* Remove manually added fmt

* Squashed 'third_party/fmt/' content from commit e69e5f977

git-subtree-dir: third_party/fmt
git-subtree-split: e69e5f977d458f2650bb346dadf2ad30c5320281

scripts/update_dependencies.sh

@@ -30,6 +30,9 @@ PROTOZERO_TAG=v1.6.2
 VTZERO_PATH="mapbox/vtzero"
 VTZERO_TAG=v1.0.1
 
+FMT_PATH="fmtlib/fmt"
+FMT_TAG=v9.1.0
+
 function update_subtree () {
     name=${1^^}
     path=$(tmpvar=${name}_PATH && echo ${!tmpvar})
@@ -53,6 +56,6 @@ function update_subtree () {
 }
 
 ## Update dependencies
-for dep in osmium variant sol rapidjson microtar protozero vtzero ; do
+for dep in osmium variant sol rapidjson microtar protozero vtzero fmt; do
     update_subtree $dep
 done