The ESP8266httpUpdate library wants to know in advance how large the file is before it starts downloading it. It wants to know this so it can tell, before trying to download (and program), whether or not there's enough space for it. If the size of the file isn't provided by the server it will report the error that you are seeing.
The size of the file is provided by the web server by means of the Content-Length HTTP response header read by HTTPClient. This header is received in advance of the file content.
Your main code appears to contain a correct link to raw .bin file,
#define URL_fw_Bin "https://raw.githubusercontent.com/programmer131/otaFiles/master/firmware.bin", and reports the following headers:
cache-control: max-age=300
content-security-policy: default-src 'none'; style-src 'unsafe-inline'; sandbox
content-type: application/octet-stream
etag: "b2ecfb5dc91587c089acdaace446b0d7b00863c9f42dffb36c7983c103d3a98a"
strict-transport-security: max-age=31536000
x-content-type-options: nosniff
x-frame-options: deny
x-xss-protection: 1; mode=block
via: 1.1 varnish (Varnish/6.0), 1.1 varnish
x-github-request-id: 8728:2B67:9AFD3:AD0EC:6008FCFF
accept-ranges: bytes
date: Thu, 21 Jan 2021 04:03:32 GMT
x-served-by: cache-bos4651-BOS
x-cache: MISS, HIT
x-cache-hits: 0, 1
x-timer: S1611201812.154162,VS0,VE1
vary: Authorization,Accept-Encoding
access-control-allow-origin: *
x-fastly-request-id: bfc9702929b91be55d7aa040465a230436918e01
expires: Thu, 21 Jan 2021 04:08:32 GMT
source-age: 20
content-length: 270016
The content-length: 270016 at the bottom shows that this should work. But your changed code that uses #define URL_fw_Bin "https://github.com/soheilpaper/ota_github_blink/blob/main/BlinkWithoutDelay_ino_esp8285.bin is to the HTML page for downloading the file, which does not report Content-length, for me anyway, but then it's the wrong URL anyway.
Regarding the "101 error", it's -101 (negative) defined here, and like they said, it is not an HTTP status code, it is just a value used by the ESP8266httpUpdate library.
