gitlab-ci: Fix using VS 16.8 toolset under VS 16.9 in CMake 3.19 branch

The 16.8 and 16.9 toolset numbers vary only in their third component.
Use CMake 3.19.7 for three-component toolset version specification
support.
24 jobs for !5918 with ci-vs-16.8-in-16.9 in 47 minutes and 8 seconds (queued for 2 seconds)
latest detached
Status Job ID Name Coverage
  Build
manual #5617789
linux docker build cmake manual
build:centos6-release
passed #5617786
linux docker build cmake
build:debian10-iwyu

00:03:43

manual #5617790
linux-3.17 linux docker build cmake manual
build:fedora33-ninja
passed #5617788
linux-3.17 linux docker build cmake
build:fedora33-sphinx

00:04:28

passed #5617787
linux-3.17 linux docker build cmake
build:fedora33-tidy

00:05:48

manual #5617792
nonconcurrent xcode-12.3 shell macos cmake manual
build:macos-makefiles
manual #5617791
nonconcurrent xcode-12.3 shell macos cmake manual
build:macos-ninja
passed #5617793
nonconcurrent msvc-19.28 vs2019 shell windows cmake manual
build:windows-vs2019-x64-ninja

00:06:33

 
  Test
created #5617794
x11 linux-3.17 linux docker cmake
test:fedora33-ninja
created #5617796
nonconcurrent xcode-12.3 shell macos cmake
test:macos-makefiles
created #5617795
nonconcurrent xcode-12.3 shell macos cmake
test:macos-ninja
passed #5617797
nonconcurrent msvc-19.28 vs2019 shell windows cmake
test:windows-vs2019-x64-ninja

00:06:03

 
  Test Ext
created #5617800
linux docker cuda-rt cmake
test:cuda10.2-nvidia
created #5617798
linux-3.17 linux docker build cmake
test:debian10-ninja
created #5617799
linux-3.17 linux docker build cmake
test:fedora33-makefiles
created #5617801
linux-3.17 linux docker build cmake
test:fedora33-ninja-multi
created #5617802
concurrent xcode-12.3 shell macos cmake
test:macos-xcode
passed #5617803
concurrent msvc-19.28 vs2019 shell windows cmake
test:windows-vs2019-x64

00:33:56

 
  External
passed cdash

passed ghostflow-check-master

passed ghostflow-check-release

passed cdash

passed cdash

passed ghostflow-check-master