Decrease 'minimum_otp_vsn' to '21' and update sheldon to 4.0.1 (#19)

Author: vkatsuba

README.md

@@ -94,6 +94,10 @@ Currently supported options for `spellcheck` configuration through `rebar.config
 ]}.
 ```
 
+## Dependencies
+
+**Required OTP version 23** or or higher. We only provide guarantees that the system runs on `OTP23+` since that's what we're testing it in, but the `minimum_otp_vsn` is `"21"` because some systems where **rebar3_sheldon** is integrated do require it.
+
 <!-- Badges -->
 [hexpm]: https://hex.pm/packages/rebar3_sheldon
 [hexpm version]: https://img.shields.io/hexpm/v/rebar3_sheldon.svg?style=flat-square

rebar.config

@@ -6,9 +6,9 @@
   warnings_as_errors,
   {i, "src"}]}.
 
-{deps, [{sheldon, "0.4.0"}]}.
+{deps, [{sheldon, "0.4.1"}]}.
 
-{minimum_otp_vsn, "23"}.
+{minimum_otp_vsn, "21"}.
 
 {project_plugins,
  [{rebar3_hex, "~> 6.11.7"},

rebar.lock

@@ -1,11 +1,11 @@
 {"1.2.0",
-[{<<"sheldon">>,{pkg,<<"sheldon">>,<<"0.4.0">>},0},
- {<<"worker_pool">>,{pkg,<<"worker_pool">>,<<"5.0.0">>},1}]}.
+[{<<"sheldon">>,{pkg,<<"sheldon">>,<<"0.4.1">>},0},
+ {<<"worker_pool">>,{pkg,<<"worker_pool">>,<<"5.1.0">>},1}]}.
 [
 {pkg_hash,[
- {<<"sheldon">>, <<"A088705B21023280C9BE442DB574ECC552AABE9575250012C3F4BFAD9AC9D297">>},
- {<<"worker_pool">>, <<"B4B867BDF7E4D6451ED82C47BD72E53C24C04518C0AB821FDC6D28BA0F8EEDE2">>}]},
+ {<<"sheldon">>, <<"1413143F9D96D30C6A18DD6746B5183F048B23AC345FF3BB92B399A5A69EBE93">>},
+ {<<"worker_pool">>, <<"61BA970F856AF8B2D85232ADC8E4B990FA1719F396FCDAD954702946395ADD80">>}]},
 {pkg_hash_ext,[
- {<<"sheldon">>, <<"08B519442050116D2B73A19A9EE4AEBE0D8898B267F790EADA1D116AD756907D">>},
- {<<"worker_pool">>, <<"1F9EBE0650BD4B2C4BD34A5BF59D29DEA37BF80C6C22AB4BE2BD02C6BA264BB6">>}]}
+ {<<"sheldon">>, <<"15E24EDDCDB42FE07AA7913DA770DBCE4EE052A37AA76E467748D4C977F463C9">>},
+ {<<"worker_pool">>, <<"59A975728E5C2B69A23D1C5EBC3B63251EC4ACBF4E9D25F1C619E3AD4B550813">>}]}
 ].