ci: go 1.25.3 in the 1st step of infra/dispatcher/Dockerfile (#2725)

Previous #2724 missed the
1st occurrence of `golang:1.25.0`.

Author: suztomo

infra/dispatcher/Dockerfile

@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-FROM golang:1.25.0 AS build
+FROM golang:1.25.3 AS build
 
 WORKDIR /src