Fixed typo in package name

Author: azonenberg

.github/workflows/build-debian.yml

@@ -48,7 +48,7 @@ jobs:
           build-essential \
           cmake \
           pkgconf \
-          libgtk-3.0-dev \
+          libgtk-3-dev \
           libsigc++-2.0-dev \
           libyaml-cpp-dev \
           catch2 \

.github/workflows/build-ubuntu.yml

@@ -50,7 +50,7 @@ jobs:
           cmake \
           ninja-build \
           pkgconf \
-          libgtk-3.0-dev \
+          libgtk-3-dev \
           libsigc++-2.0-dev \
           libyaml-cpp-dev \
           libglfw3-dev \