chore(deps) bump penlight from 1.7.0 to 1.8.0

### Summary

#### New features

  - `pretty.debug` quickly dumps a set of values to stdout for debug purposes

#### Changes

  - `pretty.write`: now also sorts non-string keys [#319](lunarmodules/Penlight#319)
  - `stringx.count` has an extra option to allow overlapping matches
    [#326](lunarmodules/Penlight#326)
  - added an extra changelog entry for `types.is_empty` on the 1.6.0 changelog, due
    to additional fixed behaviour not called out appropriately [#313](lunarmodules/Penlight#313)
  - `path.packagepath` now returns a proper error message with names tried if
    it fails

#### Fixes

  - Fix: `stringx.rfind` now properly works with overlapping matches
    [#314](lunarmodules/Penlight#314)
  - Fix: `package.searchpath` (in module `pl.compat`)
    [#328](lunarmodules/Penlight#328)
  - Fix: `path.isabs` now reports drive + relative-path as `false`, eg. "c:some/path" (Windows only)
  - Fix: OpenResty coroutines, used by `dir.dirtree`, `pl.lexer`, `pl.permute`. If
    available the original coroutine functions are now used [#329](lunarmodules/Penlight#329)
  - Fix: in `pl.strict` also predefine global `_PROMPT2`
  - Fix: in `pl.strict` apply `tostring` to the given name, in case it is not a string.
  - Fix: the lexer would not recognize numbers without leading zero; "-.123".
    See [#315](lunarmodules/Penlight#315)

kong-2.1.0-0.rockspec

@@ -14,7 +14,7 @@ dependencies = {
   "inspect == 3.1.1",
   "luasec == 0.9",
   "luasocket == 3.0-rc1",
-  "penlight == 1.7.0",
+  "penlight == 1.8.0",
   "lua-resty-http == 0.15",
   "lua-resty-jit-uuid == 0.0.7",
   "lua-ffi-zlib == 0.5",