Use njs 0.8.7

[macbre]

Changes with njs 0.8.7                                       22 Oct 2024
    nginx modules:
    *) Bugfix: eliminated unnecessary VM creation.
       Previously, njs consumed memory proportionally to the number of
       nginx locations. The issue was introduced in 9b674412 (0.8.6).
    *) Improvement: added strict syntax validation for js_body_filter.
    *) Improvement: improved error messages for module loading
       failures.
    Core:
    *) Feature: implemented fs.readlink() and friends.
    *) Improvement: implemented lazy stack symbolization.
    *) Bugfix: fixed heap-buffer-overflow in Buffer.prototype.indexOf().
       The issue was introduced in 5d15a8d6 (0.8.6).
    *) Bugfix: fixed Buffer.prototype.lastIndexOf() when `from` is
       provided.