Pin GitLink version to speed up Cake script

[jnm2]

Based on a tip from the Cake team.

[mikkelbu]

Are we sure about this tip? For this PR the current build on AppVeyor takes almost 2 minutes in the GitLink target

Task                          Duration            
--------------------------------------------------
Setup                         00:00:02.1671101    
NuGetRestore                  00:00:09.3710531    
Build                         00:00:32.3807515    
Test45                        00:00:34.0428569    
Test40                        00:00:33.9991150    
Test35                        00:00:37.3628111    
TestNetStandard14             00:00:43.5626333    
TestNetStandard20             00:00:32.0430121    
CheckForError                 00:00:00.0011337    
CreateImage                   00:00:00.2438897    
GitLink                       00:01:54.8829918    
PackageFramework              00:00:02.5229281    
PackageZip                    00:00:02.8158967    
UploadArtifacts               00:00:07.5772104    
Teardown                      00:00:00.0007935    
--------------------------------------------------
Total:                        00:05:52.9750139  

Usually, this takes between 35 and 40 seconds (I looked at 6 other builds). I'll just try to rebuild this PR on AppVeyor to see if it changes anything.

EDIT: Two rebuilds of the PR gives 36.16 and 36.52 for the GitLink target, so I don't see the speed up unless it is from the time the script is invoked and to the first target "Setup" (but this also varies a lot).

[jnm2]

I don't see the speed up unless it is from the time the script is invoked and to the first target "Setup" (but this also varies a lot).

This is where the speedup is, before the build script is compiled. It removes the need for an additional nuget.org gallery query to determine the latest version.

I also just saw this tip as a warning printed out in the console in recent versions of Cake:

The 'tool' directive is attempting to install the 'GitLink' package
without specifying a package version number.
More information on this can be found at https://cakebuild.net/docs/tutorials/pinning-cake-version
It's not recommended, but you can explicitly override this warning
by configuring the Skip Package Version Check setting to true
(i.e. command line parameter "--settings_skippackageversioncheck=true",
environment variable "CAKE_SETTINGS_SKIPPACKAGEVERSIONCHECK=true",
read more about configuration at https://cakebuild.net/docs/fundamentals/configuration)

[mikkelbu]

LGTM, but primarily to get the warning to disappear as we have enough output as it is :)