.pidlock -> .pid to match convention

Author: IanButterworth

src/Registry/Registry.jl

@@ -162,7 +162,7 @@ function download_registries(io::IO, regs::Vector{RegistrySpec}, depot::String=d
     populate_known_registries_with_urls!(regs)
     regdir = joinpath(depot, "registries")
     isdir(regdir) || mkpath(regdir)
-    Pidfile.mkpidlock(joinpath(regdir, ".pidlock")) do # only allow one julia process to download and install registries at a time
+    Pidfile.mkpidlock(joinpath(regdir, ".pid")) do # only allow one julia process to download and install registries at a time
         registry_urls = pkg_server_registry_urls()
         for reg in regs
             if reg.path !== nothing && reg.url !== nothing
@@ -349,7 +349,7 @@ function update(regs::Vector{RegistrySpec} = RegistrySpec[]; io::IO=stderr_f(),
     for reg in unique(r -> r.uuid, find_installed_registries(io, regs); seen=Set{UUID}())
         let reg=reg
             regpath = pathrepr(reg.path)
-            Pidfile.mkpidlock(joinpath(dirname(dirname(reg.path)), ".$(reg.name).pidlock")) do # only allow one julia process to update a registry at a time
+            Pidfile.mkpidlock(joinpath(dirname(dirname(reg.path)), ".$(reg.name).pid")) do # only allow one julia process to update a registry at a time
                 if reg.tree_info !== nothing
                     printpkgstyle(io, :Updating, "registry at " * regpath)
                     old_hash = reg.tree_info

src/Types.jl

@@ -468,7 +468,7 @@ function write_env_usage(source_file::AbstractString, usage_filepath::AbstractSt
     timestamp = now()
 
     ## Atomically write usage file using process id locking
-    Pidfile.mkpidlock(usage_file * ".pidlock") do
+    Pidfile.mkpidlock(usage_file * ".pid") do
         usage = if isfile(usage_file)
             TOML.parsefile(usage_file)
         else