libmaxminddb: update to 1.4.3.

ChangeLog:

## 1.4.3 - 2020-08-06

* On Windows, always call `CreateFileW` instead of `CreateFile`.
  `CreateFile` could be mapped to `CreateFileA` and not work as expected.
  Pull request by Sandu Liviu Catalin. GitHub #228.
* Fixed use of uninitialized memory in `dump_entry_data_list()` that could
  cause a heap buffer flow in `mmdblookup`. As part of this fix, most uses
  of `malloc` were replaced with `calloc`. Reported by azhou. GitHub #236.

## 1.4.2 - 2019-11-02

* The 1.4.0 release introduced a change that increased the size of `MMDB_s`,
  unintentionally causing an ABI break. This release reverts the relevant
  commit.

## 1.4.1 - 2019-11-01

* The man page links for function calls were not generated correctly in
  1.4.0. This has been corrected.

## 1.4.0 - 2019-11-01

* A negative array index may now be used with `MMDB_get_value`,
  `MMDB_vget_value`, and `MMDB_aget_value`. This specifies the element
  from the end of the array. For instance, `-1` would refer to the
  last element of the array. PR by Kyle Box. GitHub #205.
* On Windows, the file name passed to `MMDB_open` is now expected to be
  UTF-8 encoded. This allows Unicode characters to be used in file names.
  As part of this change, `mmdblookup` on Windows now converts its
  arguments to UTF-8. PR by Gerald Combs. GitHub #189 & #191.
* Fix a memory leak that occurred when freeing an `MMDB_s` where the
  database had no languages defined in the metadata. If you are using an
  official MaxMind database, this leak does not affect you. Pull request
  by K坦kai P辿ter. GitHub #180.
* Add `--disable-binaries` option to `configure`. Pull request by Fabrice
  Fontaine. GitHub #166.
* Previous releases incorrectly included `*.Po` files in the `t` directory.
  This has been corrected. Reported by Daniel Macks. GitHub #168.
* The internal use of the `MMDB_s` now has the `const` modifier. Public
  functions that accepted an `MMDB_s` as an argument now also declare it as
  `const`. Pull request by Kurt Johnson. GitHub #199.
* `mmdblookup` now displays the prefix length for the record when using
  the verbose flag. GitHub #172.

(fcambus)