Rework tests to only perform a single fetch data from IANA servers

[omus]

The current TimeZones.jl setup fetches a specific version of the tzdata from the IANA services for running tests. When running on CI this data is always fetched at least once. It was noticed in #441 that we perform a second fetch from the IANA services in tzdata/build.jl which hasn't been problematic but causes unnecessary load on their servers.

We may also want to look into using GHA caching to avoid downloading from their servers entirely.

[omus]

Definitely should use some GHA caching:

[ Info: Loading tzdata 2016j
[ Info: Downloading tzdata 2016j archive
ERROR: LoadError: InitError: RequestError: Operation too slow. Less than 1 bytes/sec transferred the last 20 seconds while requesting https://data.iana.org/time-zones/releases/tzdata2016j.tar.gz

– https://github.com/JuliaTime/TimeZones.jl/actions/runs/5946262840/job/16126554201#step:6:131

Looks like the tzdata_version check may also be an isssue:

[ Info: Downloading Windows to POSIX timezone ID XML version: release-43-1
[ Info: Compiling Windows time zone name translation
[ Info: Loading tzdata 2016j
[ Info: Downloading tzdata 2016j archive
[ Info: Decompressing tzdata 2016j region data
[ Info: Compiling tzdata 2016j region data
tzdata_version: Error During Test at D:\a\TimeZones.jl\TimeZones.jl\test\tzdata\version.jl:57
  Got exception outside of a @test
  RequestError: HTTP/1.1 200 OK (Operation too slow. Less than 1 bytes/sec transferred the last 20 seconds) while requesting https://data.iana.org/time-zones/releases/
  Stacktrace:
    [1] (::Downloads.var"#9#18"{IOBuffer, Base.DevNull, Nothing, Vector{Pair{String, String}}, Float64, Nothing, Bool, Nothing, Bool, String, Bool, Bool})(easy::Downloads.Curl.Easy)
      @ Downloads C:\hostedtoolcache\windows\julia\1.9.2\x64\share\julia\stdlib\v1.9\Downloads\src\Downloads.jl:388
    [2] with_handle(f::Downloads.var"#9#18"{IOBuffer, Base.DevNull, Nothing, Vector{Pair{String, String}}, Float64, Nothing, Bool, Nothing, Bool, String, Bool, Bool}, handle::Downloads.Curl.Easy)
      @ Downloads.Curl C:\hostedtoolcache\windows\julia\1.9.2\x64\share\julia\stdlib\v1.9\Downloads\src\Curl\Curl.jl:90
    [3] #8
      @ C:\hostedtoolcache\windows\julia\1.9.2\x64\share\julia\stdlib\v1.9\Downloads\src\Downloads.jl:329 [inlined]
    [4] arg_write(f::Downloads.var"#8#17"{Base.DevNull, Nothing, Vector{Pair{String, String}}, Float64, Nothing, Bool, Nothing, Bool, String, Bool, Bool}, arg::IOBuffer)
      @ ArgTools C:\hostedtoolcache\windows\julia\1.9.2\x64\share\julia\stdlib\v1.9\ArgTools\src\ArgTools.jl:134
    [5] #7
      @ C:\hostedtoolcache\windows\julia\1.9.2\x64\share\julia\stdlib\v1.9\Downloads\src\Downloads.jl:328 [inlined]
    [6] arg_read
      @ C:\hostedtoolcache\windows\julia\1.9.2\x64\share\julia\stdlib\v1.9\ArgTools\src\ArgTools.jl:76 [inlined]
    [7] request(url::String; input::Nothing, output::IOBuffer, method::Nothing, headers::Vector{Pair{String, String}}, timeout::Float64, progress::Nothing, verbose::Bool, debug::Nothing, throw::Bool, downloader::Nothing)
      @ Downloads C:\hostedtoolcache\windows\julia\1.9.2\x64\share\julia\stdlib\v1.9\Downloads\src\Downloads.jl:327
    [8] request
      @ C:\hostedtoolcache\windows\julia\1.9.2\x64\share\julia\stdlib\v1.9\Downloads\src\Downloads.jl:295 [inlined]
    [9] #3
      @ C:\hostedtoolcache\windows\julia\1.9.2\x64\share\julia\stdlib\v1.9\Downloads\src\Downloads.jl:233 [inlined]
   [10] arg_write(f::Downloads.var"#3#4"{Nothing, Vector{Pair{String, String}}, Float64, Nothing, Bool, Nothing, Nothing, String}, arg::IOBuffer)
      @ ArgTools C:\hostedtoolcache\windows\julia\1.9.2\x64\share\julia\stdlib\v1.9\ArgTools\src\ArgTools.jl:134
   [11] #download#2
      @ C:\hostedtoolcache\windows\julia\1.9.2\x64\share\julia\stdlib\v1.9\Downloads\src\Downloads.jl:232 [inlined]
   [12] download
      @ C:\hostedtoolcache\windows\julia\1.9.2\x64\share\julia\stdlib\v1.9\Downloads\src\Downloads.jl:221 [inlined]
   [13] tzdata_versions()
      @ TimeZones.TZData D:\a\TimeZones.jl\TimeZones.jl\src\tzdata\download.jl:56
   [14] tzdata_latest_version()
      @ TimeZones.TZData D:\a\TimeZones.jl\TimeZones.jl\src\tzdata\download.jl:81
   [15] tzdata_version()
      @ TimeZones.TZData D:\a\TimeZones.jl\TimeZones.jl\src\tzdata\version.jl:92
   [16] (::var"#16#19")()
      @ Main D:\a\TimeZones.jl\TimeZones.jl\test\tzdata\version.jl:69
   [17] withenv(f::var"#16#19", keyvals::Pair{String, String})
      @ Base .\env.jl:197
   [18] macro expansion
      @ D:\a\TimeZones.jl\TimeZones.jl\test\tzdata\version.jl:68 [inlined]
   [19] macro expansion
...

– https://github.com/JuliaTime/TimeZones.jl/actions/runs/5946262840/job/16126554082#step:6:137