Add compat with Julia 1.4

src/plugins/git.jl

@@ -80,12 +80,8 @@ function posthook(p::Git, ::Template, pkg_dir::AbstractString)
     LibGit2.with(GitRepo(pkg_dir)) do repo
         LibGit2.add!(repo, ".")
         msg = "Files generated by PkgTemplates"
-        # TODO: Newer versions of Julia will not have Pkg.installed.
-        installed = Pkg.installed()
-        if haskey(installed, "PkgTemplates")
-            ver = string(installed["PkgTemplates"])
-            msg *= "\n\nPkgTemplates version: $ver"
-        end
+        v = version_of("PkgTemplates")
+        v === nothing || (msg *= "\n\nPkgTemplates version: $v")
         commit(p, repo, pkg_dir, msg)
     end
 end
@@ -99,3 +95,14 @@ function commit(p::Git, repo::GitRepo, pkg_dir::AbstractString, msg::AbstractStr
 end
 
 needs_username(::Git) = true
+
+if isdefined(Pkg, :dependencies)
+    function version_of(pkg::AbstractString)
+        for p in values(Pkg.dependencies())
+            p.name == pkg && return p.version
+        end
+        return nothing
+    end
+else
+    version_of(pkg::AbstractString) = get(Pkg.installed(), pkg, nothing)
+end

test/git.jl

@@ -38,7 +38,7 @@
     @testset "Adds version to commit message" begin
         # We're careful to avoid a Pkg.update as it triggers Cassette#130.
         t = tpl(; disable_defaults=[Tests], plugins=[Git()])
-        mock(Pkg.installed => () -> Dict("PkgTemplates" => v"1.2.3")) do _pi
+        mock(PT.version_of => _p -> v"1.2.3") do _i
             with_pkg(t) do pkg
                 pkg_dir = joinpath(t.dir, pkg)
                 LibGit2.with(GitRepo(pkg_dir)) do repo

test/runtests.jl

@@ -6,7 +6,7 @@ using Random: Random
 using Test: @test, @testset, @test_throws
 
 using ReferenceTests: @test_reference
-using SimpleMock: Mock, mock
+using SimpleMock: mock
 using Suppressor: @suppress
 
 using PkgTemplates
@@ -30,7 +30,9 @@ function with_pkg(f::Function, t::Template, pkg::AbstractString=pkgname())
     try
         f(pkg)
     finally
-        haskey(Pkg.installed(), pkg) && @suppress Pkg.rm(pkg)
+        # On 1.4, this sometimes won't work, but the error is that the package isn't installed.
+        # We're going to delete the package directory anyways, so just ignore any errors.
+        PT.version_of(pkg) === nothing || try @suppress Pkg.rm(pkg) catch; end
         rm(joinpath(t.dir, pkg); recursive=true, force=true)
     end
 end