Fix python-version in travis after_success.sh for linux build

The upstream AppImage for python3.7.x got upgraded from 3.7.11 to
3.7.12, causing the script to fail.

travis/linux/after_success.sh

@@ -46,10 +46,10 @@ chmod a+x linuxdeployqt-7-x86_64.AppImage
 ./linuxdeployqt-7-x86_64.AppImage appdir/GoldenCheetah -verbose=2 -bundle-non-qt-libs -exclude-libs=libqsqlmysql,libqsqlpsql,libnss3,libnssutil3,libxcb-dri3.so.0 -unsupported-allow-new-glibc
 
 # Add Python and core modules
-wget https://github.com/niess/python-appimage/releases/download/python3.7/python3.7.11-cp37-cp37m-manylinux1_x86_64.AppImage
-chmod +x python3.7.11-cp37-cp37m-manylinux1_x86_64.AppImage
-./python3.7.11-cp37-cp37m-manylinux1_x86_64.AppImage --appimage-extract
-rm -f python3.7.11-cp37-cp37m-manylinux1_x86_64.AppImage
+wget https://github.com/niess/python-appimage/releases/download/python3.7/python3.7.12-cp37-cp37m-manylinux1_x86_64.AppImage
+chmod +x python3.7.12-cp37-cp37m-manylinux1_x86_64.AppImage
+./python3.7.12-cp37-cp37m-manylinux1_x86_64.AppImage --appimage-extract
+rm -f python3.7.12-cp37-cp37m-manylinux1_x86_64.AppImage
 export PATH="$(pwd)/squashfs-root/usr/bin:$PATH"
 pip install --upgrade pip
 pip install -r Python/requirements.txt