ci: use action to avoid rate limiting

[Madoshakalaka]

size comparison workflow was flaky due to rate limiting

thread 'main' (2243) panicked at tools/build-examples/src/lib.rs:35:9:
GitHub API request failed with status: 403 Forbidden. Details: {"message":"API rate limit exceeded for 13.83.216.100. (But here's the good news: Authenticated requests get a higher rate limit. Check out the documentation for more details.)","documentation_url":"https://docs.github.com/rest/overview/resources-in-the-rest-api#rate-limiting"}

this fixes it by using an action authenticating with our github token

[github-actions]

Size Comparison

Details

examples	master (KB)	pull request (KB)	diff (KB)	diff (%)
async_clock	98.452	98.452	0	0.000%
boids	166.530	166.530	0	0.000%
communication_child_to_parent	91.539	91.539	0	0.000%
communication_grandchild_with_grandparent	102.650	102.650	0	0.000%
communication_grandparent_to_grandchild	99.043	99.043	0	0.000%
communication_parent_to_child	88.910	88.910	0	0.000%
contexts	104.032	104.032	0	0.000%
counter	85.586	85.586	0	0.000%
counter_functional	85.856	85.856	0	0.000%
dyn_create_destroy_apps	88.752	88.752	0	0.000%
file_upload	98.341	98.341	0	0.000%
function_delayed_input	91.269	91.269	0	0.000%
function_memory_game	169.522	169.522	0	0.000%
function_router	328.310	328.310	0	0.000%
function_todomvc	161.704	161.704	0	0.000%
futures	236.300	236.300	0	0.000%
game_of_life	103.982	103.982	0	0.000%
immutable	246.113	246.113	0	0.000%
inner_html	80.070	80.070	0	0.000%
js_callback	107.617	107.617	0	0.000%
keyed_list	179.237	179.237	0	0.000%
mount_point	83.287	83.287	0	0.000%
nested_list	112.840	112.840	0	0.000%
node_refs	90.932	90.932	0	0.000%
password_strength	1743.423	1743.423	0	0.000%
portals	92.409	92.409	0	0.000%
router	302.058	302.058	0	0.000%
suspense	111.870	111.870	0	0.000%
timer	88.355	88.355	0	0.000%
timer_functional	96.041	96.041	0	0.000%
todomvc	141.810	141.810	0	0.000%
two_apps	85.441	85.441	0	0.000%
web_worker_fib	133.247	133.247	0	0.000%
web_worker_prime	184.469	184.469	0	0.000%
webgl	82.707	82.707	0	0.000%

✅ None of the examples has changed their size significantly.

[Madoshakalaka]

on a second thought

tools/build-examples/src/bin/update-wasm-opt.rs uses the function too, but that binary is not used in the pipelines.
it should call the api function directly

if anybody sees this feel free to make the change