Update cairo-lang version to 2.6.4 (#1799)

* update cairo-lang to 2.6.4

* update CHANGELOG.md

* update serialization of air_public_input

* CHANGELOG.md

* update CHANGELOG.md

Author: FrancoGiachetta

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 #### Upcoming Changes
 
+* chore: bump `cairo-lang-` dependencies to 2.6.4 [#1799](https://github.com/lambdaclass/cairo-vm/pull/1799)
+  * fix: revert breaking change on public input serialization
+
 * fix: Remove validation of CairoPie memory values [#1783](https://github.com/lambdaclass/cairo-vm/pull/1783)
 
 * fix: Handle `GasBuiltin` in cairo1-run crate [#1789](https://github.com/lambdaclass/cairo-vm/pull/1789)