Bump to 0.4.3: pin glibc >=2.17 via stdlib('c')

Binary built on ubuntu-latest (glibc 2.39) was incompatible with
Ubuntu 22.04 (glibc 2.35). Add stdlib('c') + variants.yaml with
c_stdlib_version 2.17 so rattler-build uses the older sysroot.

Verified locally: binary requires only GLIBC_2.14.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Entire-Checkpoint: e192bd64bf42

Author: facontidavide

conda.recipe/recipe.yaml

@@ -1,5 +1,5 @@
 context:
-  version: "0.4.2"
+  version: "0.4.3"
 
 package:
   name: pj-bridge-ros2-${{ ros_distro }}
@@ -26,6 +26,7 @@ build:
 requirements:
   build:
     - ${{ compiler('c') }}
+    - ${{ stdlib('c') }}
     - ${{ compiler('cxx') }}
     - cmake >=3.14
     - ninja

conda.recipe/variants.yaml

@@ -0,0 +1,4 @@
+c_stdlib:
+  - sysroot
+c_stdlib_version:
+  - "2.17"