CI gdal-master conda: patch version number to X.Y.99

Fixes OSGeo#11663

```
$ cat ~/gdal-feedstock/recipe/meta.yaml | sed -E 's/set version = "([0-9]+)\.([0-9]+)\.([0-9]+)"/set version = "\1.\2.99"/' | head -n 1
{% set version = "3.10.99" %}
```

ci/travis/conda/setup.sh

@@ -22,6 +22,9 @@ cd gdal-feedstock
 patch -p1 < ../ci/travis/conda/libgdal-adbc.patch
 patch -p1 < ../ci/travis/conda/muparser.patch
 
+# Patch version = "X.Y.Z" to "X.Y.99"
+sed -i -E 's/set version = "([0-9]+)\.([0-9]+)\.([0-9]+)"/set version = "\1.\2.99"/' recipe/meta.yaml
+
 cat > recipe/recipe_clobber.yaml <<EOL
 source:
   path: ../../../gdal