How to use Dub and Digger to build Pull Requests?

[Quirin Schroll]

The dlang-bot writes a message to every PR:
> #### Testing this PR locally
>
> If you don't have a local development environment setup, you 
> can use Digger to test this PR:
> ```bash
> dub run digger -- build "master + dmd#<<ISSUE-NUMBER>>"
> ```

I installed the current DMD (version 2.103.1) and executed the 
above command; I’m getting the following error:
```
object.Exception@%LOCALAPPDATA%\dub\packages\ae-0.0.3236\ae\sys\d\manager.d(898): Command ["make", "-f", "win32.mak", "MODEL=32", "HOST_DC=C:\\Users\\qschroll\\Documents\\d\\mydmd\\work\\dl\\dmd-2.079.0\\dmd2/windows/bin\\dmd.exe", "dmd"] failed with status 1
----------------
0x00007FF605F8ECE7 in d_throwc
0x00007FF605B94CAC in 
std.exception.bailOut!(object.Exception).bailOut at 
C:\D\dmd2\windows\bin64\..\..\src\phobos\std\exception.d(518)
0x00007FF605B94BB9 in 
std.exception.enforce!().enforce!bool.enforce at 
C:\D\dmd2\windows\bin64\..\..\src\phobos\std\exception.d(439)
0x00007FF605E09EA9 in ae.sys.d.manager.DManager.Component.run at 
C:\D\dmd2\windows\bin64\..\..\src\phobos\std\exception.d(436)
0x00007FF605E0C79F in ae.sys.d.manager.DManager.DMD.performBuild 
at 
%LOCALAPPDATA%\dub\packages\ae-0.0.3236\ae\sys\d\manager.d(1185)
0x00007FF605E06B4B in 
ae.sys.d.manager.DManager.Component.needBuild at 
%LOCALAPPDATA%\dub\packages\ae-0.0.3236\ae\sys\d\manager.d(552)
0x00007FF605E07522 in 
ae.sys.d.manager.DManager.Component.needInstalled at 
%LOCALAPPDATA%\dub\packages\ae-0.0.3236\ae\sys\d\manager.d(702)
0x00007FF605E18A22 in ae.sys.d.manager.DManager.build at 
%LOCALAPPDATA%\dub\packages\ae-0.0.3236\ae\sys\d\manager.d(2322)
0x00007FF605D79E95 in custom.runBuild at 
%LOCALAPPDATA%\dub\packages\digger-3.0.9\digger\custom.d(64)
0x00007FF605D7AAD4 in custom.buildCustom at 
%LOCALAPPDATA%\dub\packages\digger-3.0.9\digger\custom.d(135)
0x00007FF605D7B0E6 in digger.Digger.build at 
%LOCALAPPDATA%\dub\packages\digger-3.0.9\digger\digger.d(72)
0x00007FF605ED121D in ae.utils.funopt.funopt!(build, 
FunOptConfig(null), usageFun).funopt at 
%LOCALAPPDATA%\dub\packages\ae-0.0.3236\ae\utils\funopt.d(308)
0x00007FF605ECE874 in 
ae.utils.funopt.funoptDispatch!(digger.Digger, 
FunOptConfig(null), usageFun).funoptDispatch.fun at 
%LOCALAPPDATA%\dub\packages\ae-0.0.3236\ae\utils\funopt.d(844)
0x00007FF605EF8432 in 
ae.utils.funopt.funoptDispatch!(digger.Digger, 
FunOptConfig(null), usageFun).funoptDispatch.funopt!(fun, 
FunOptConfig([config.stopOnFirstNonOption]), myUsageFun).funopt 
at %LOCALAPPDATA%\dub\packages\ae-0.0.3236\ae\utils\funopt.d(308)
0x00007FF605ECE660 in 
ae.utils.funopt.funoptDispatch!(digger.Digger, 
FunOptConfig(null), usageFun).funoptDispatch at 
%LOCALAPPDATA%\dub\packages\ae-0.0.3236\ae\utils\funopt.d(858)
0x00007FF605D7C661 in digger.digger at 
%LOCALAPPDATA%\dub\packages\digger-3.0.9\digger\digger.d(275)
0x00007FF605D7CF75 in digger.main!(digger).main.run at 
%LOCALAPPDATA%\dub\packages\ae-0.0.3236\ae\utils\main.d(36)
0x00007FF605D7E292 in 
digger.main!(digger).main.runCatchingException!(std.getopt.GetOptException, "Usage error").runCatchingException at %LOCALAPPDATA%\dub\packages\ae-0.0.3236\ae\utils\main.d(47)
0x00007FF605D7CF3E in D main at 
%LOCALAPPDATA%\dub\packages\ae-0.0.3236\ae\utils\main.d(70)
0x00007FF605FEA853 in void rt.dmain2._d_run_main2(char[][], 
ulong, extern (C) int function(char[][])*).runAll().__lambda2()
0x00007FF605FEA64F in void rt.dmain2._d_run_main2(char[][], 
ulong, extern (C) int function(char[][])*).tryExec(scope void 
delegate())
0x00007FF605FEA76F in void rt.dmain2._d_run_main2(char[][], 
ulong, extern (C) int function(char[][])*).runAll()
0x00007FF605FEA64F in void rt.dmain2._d_run_main2(char[][], 
ulong, extern (C) int function(char[][])*).tryExec(scope void 
delegate())
0x00007FF605FEA41A in d_run_main2
0x00007FF605FB4BB9 in d_run_main
0x00007FF605D7CFB2 in digger._d_cmain!().main at 
C:\D\dmd2\windows\bin64\..\..\src\druntime\import\core\internal\entrypoint.d(29)
0x00007FF6060C5398 in __scrt_common_main_seh at 
D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl(288)
0x00007FFED11C7604 in BaseThreadInitThunk
0x00007FFED2EC26A1 in RtlUserThreadStart
Error Program exited with code 1
```

(I replaced `C:\Users\`my user name`\AppData\Local` by 
`%LOCALAPPDATA%`.)