Wget failures connecting to GitHub on Ubuntu 20

[Jeffrey Walton]

Hi Everyone,

This caught me by surprise today:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.3 LTS
Release:        20.04
Codename:       focal

$ wget -O main.cxx
https://raw.githubusercontent.com/austin-clifton/cryptopp-chacha-asm-test/main/src/main.cpp
                      --2021-09-17 21:13:12--
https://raw.githubusercontent.com/austin-clifton/cryptopp-chacha-asm-test/main/src/main.cpp
Resolving raw.githubusercontent.com (raw.githubusercontent.com)...
185.199.111.133, 185.199.110.133, 185.199.109.133, ...
Connecting to raw.githubusercontent.com
(raw.githubusercontent.com)|185.199.111.133|:443... connected.
ERROR: cannot verify raw.githubusercontent.com's certificate, issued
by 'CN=DigiCert SHA2 High Assurance Server
CA,OU=www.digicert.com,O=DigiCert Inc,C=US':
  Unable to locally verify the issuer's authority.
To connect to raw.githubusercontent.com insecurely, use
`--no-check-certificate'.

$ command -v wget
/usr/bin/wget

$ wget --version
GNU Wget 1.20.3 built on linux-gnu.

-cares +digest -gpgme +https +ipv6 +iri +large-file -metalink +nls
+ntlm +opie +psl +ssl/openssl

Wgetrc:
    /etc/wgetrc (system)
Locale:
    /usr/share/locale
Compile:
    gcc -DHAVE_CONFIG_H -DSYSTEM_WGETRC="/etc/wgetrc"
    -DLOCALEDIR="/usr/share/locale" -I. -I../../src -I../lib
    -I../../lib -Wdate-time -D_FORTIFY_SOURCE=2 -DHAVE_LIBSSL -DNDEBUG
    -g -O2 -fdebug-prefix-map=/build/wget-OYIfr9/wget-1.20.3=.
    -fstack-protector-strong -Wformat -Werror=format-security
    -DNO_SSLv2 -D_FILE_OFFSET_BITS=64 -g -Wall
Link:
    gcc -DHAVE_LIBSSL -DNDEBUG -g -O2
    -fdebug-prefix-map=/build/wget-OYIfr9/wget-1.20.3=.
    -fstack-protector-strong -Wformat -Werror=format-security
    -DNO_SSLv2 -D_FILE_OFFSET_BITS=64 -g -Wall -Wl,-Bsymbolic-functions
    -Wl,-z,relro -Wl,-z,now -lpcre2-8 -luuid -lidn2 -lssl -lcrypto -lz
    -lpsl ftp-opie.o openssl.o http-ntlm.o ../lib/libgnu.a