[Doc] Update FAQ (#993)

* [Doc] Update FAQ

* update doc

* Update faq.md
Co-authored-by: Wenwei Zhang <40779233+ZwwWayne@users.noreply.github.com>

docs/faq.md

@@ -24,3 +24,15 @@ We list some potential troubles encountered by users and developers, along with
   ``TypeError: expected dtype object, got 'numpy.dtype[bool_]'``
 
   please downgrade numpy to < 1.20.0 or install numba == 0.48 from source, because in numpy == 1.20.0, `np.dtype` produces subclass due to API change. Please refer to [here](https://github.com/numba/numba/issues/6041) for more details.
+
+- If you face the error shown below when importing pycocotools:
+
+  ``ValueError: numpy.ndarray size changed, may indicate binary incompatibility. Expected 88 from C header, got 80 from PyObject``
+
+  please downgrade pycocotools to 2.0.1 because of the incompatibility between the newest pycocotools and numpy < 1.20.0. Or you can compile and install the latest pycocotools from source as below:
+
+  ``pip install -e "git+https://github.com/cocodataset/cocoapi#egg=pycocotools&subdirectory=PythonAPI"``
+
+  or
+
+  ``pip install -e "git+https://github.com/ppwwyyxx/cocoapi#egg=pycocotools&subdirectory=PythonAPI"``

docs_zh-CN/faq.md

@@ -24,3 +24,15 @@
   ``TypeError: expected dtype object, got 'numpy.dtype[bool_]'``
 
     请将 numpy 的版本降级至 < 1.20.0，或者从源码安装 numba == 0.48，这是由于 numpy == 1.20.0 改变了 API，使得在调用 `np.dtype` 会产生子类。请参考 [这里](https://github.com/numba/numba/issues/6041) 获取更多细节。
+
+- 如果您在导入 pycocotools 相关包时遇到下面的问题：
+
+  ``ValueError: numpy.ndarray size changed, may indicate binary incompatibility. Expected 88 from C header, got 80 from PyObject``
+
+  请将 pycocotools 的版本降级至 2.0.1，这是由于最新版本的 pycocotools 与 numpy < 1.20.0 不兼容。或者通过下面的方式从源码进行编译来安装最新版本的 pycocotools ：
+
+  ``pip install -e "git+https://github.com/cocodataset/cocoapi#egg=pycocotools&subdirectory=PythonAPI"``
+
+  或者
+
+  ``pip install -e "git+https://github.com/ppwwyyxx/cocoapi#egg=pycocotools&subdirectory=PythonAPI"``