CI: Add python dependencies

Littlecheck needs it.

.builds/alpine.yml

@@ -5,6 +5,7 @@ packages:
   - ncurses-dev
   - pcre2-dev
   - expect
+  - python
 sources:
   - https://git.sr.ht/~faho/fish
 tasks:

.builds/arch.yml

@@ -3,6 +3,7 @@ packages:
   - cmake
   - ninja
   - expect
+  - python
 sources:
   - https://git.sr.ht/~faho/fish
 tasks:

.builds/freebsd.yml

@@ -7,6 +7,7 @@ packages:
   - cmake
   - gmake
   - pcre2
+  - python
 sources:
   - https://git.sr.ht/~faho/fish
 tasks:

.travis.yml

@@ -13,6 +13,7 @@ matrix:
             - gettext
             - libncurses5-dev
             - libpcre2-dev
+            - python
       env:
           - CXXFLAGS="-g -O2 -Werror=address"
     - os: linux
@@ -24,6 +25,7 @@ matrix:
             - gettext
             - lib32ncurses5-dev
             - g++-multilib
+            - python
       env:
           - CXXFLAGS="-g -O2 -m32 -Werror=address" CFLAGS="-g -m32"
     - os: linux
@@ -39,6 +41,7 @@ matrix:
             - gettext
             - libncurses5-dev
             - libpcre2-dev
+            - python
     - os: osx
       before_install:
         - brew update