`./bootstrap.sh` fails if `OUTDIR` doesn't exist

[chrisyxlee]

Error

❯ make bin/bindl
make: bindl: Command not found
curl --location https://bindl.dev/bootstrap.sh | OUTDIR=/Users/croissant/Projects/matcha/bin bash
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   103  100   103    0     0   1470      0 --:--:-- --:--:-- --:--:--  1661
100  2058  100  2058    0     0   6801      0 --:--:-- --:--:-- --:--:-- 89478
[bootstrap] Hello! The sole purpose of my existence is to bootstrap bindl.
[bootstrap] I have found myself in x86_64 machine running Darwin.
[bootstrap] I expect the archive to be named bindl-Darwin-x86_64.tar.gz.
[bootstrap] Detected non-interactive mode, prompt implictly proceeds
[bootstrap] Working in /tmp/bootstrap-bindl-CHeLb
[bootstrap] Downloading (1/2): checksums.txt
[bootstrap] Downloading (2/2): bindl-Darwin-x86_64.tar.gz
[bootstrap] Downloaded: bindl-Darwin-x86_64.tar.gz checksums.txt
[bootstrap] Verifying checksums
bindl-Darwin-x86_64.tar.gz: OK
[bootstrap] Printing program version
version: 0.0.5 (go1.18)
commit: 4b5fba05cd01309ca791844d65e97a3309b7ec0d
date: 2022-04-12T20:40:55Z
mv: rename /tmp/bootstrap-bindl-CHeLb/bindl to /Users/croissant/Projects/matcha/bin/.: No such file or directory
make: *** [bin/bindl] Error 1

Workaround

################
# DEPENDENCIES #
################

# To download more dependencies.
bin/bindl:
        mkdir -p ${PWD}/bin
        curl --location https://bindl.dev/bootstrap.sh | OUTDIR=${PWD}/bin bash

[wilsonehusin]

@chrisyxlee wanna submit the PR for mkdir -p?