First naked-singularity containers hosted on GitHub Container Registry

Successfully tested by pushing containers [1] built on Jetstream to
GitHub Container Registry (GHCR), pulling containers [2] hosted on
GHCR to Expanse, and then running osu_bw and osu_latency benchmarks.

[1]

export GH_PAT='<GITHUB_PERSONAL_ACCESS_TOKEN>'
singularity push --docker-login mkandes --docker-password "${GH_PAT}" \
  omb-5.6.3-ubuntu-18.04-openmpi-3.1.6.sif \
  oras://ghcr.io/mkandes/naked-singularity:omb-5.6.3-ubuntu-18.04-openmpi-3.1.6

[2]

singularity pull oras://ghcr.io/mkandes/naked-singularity:omb-5.6.3-ubuntu-18.04-openmpi-3.1.6

definition-files/omb/Singularity.omb-5.6.3-ubuntu-18.04-openmpi-3.1.6

-Bootstrap: shub
-From: mkandes/naked-singularity:ubuntu-18.04-openmpi-3.1.6
+Bootstrap: oras
+From: ghcr.io/mkandes/naked-singularity:ubuntu-18.04-openmpi-3.1.6
 
 %labels
 
@@ -10,7 +10,7 @@ From: mkandes/naked-singularity:ubuntu-18.04-openmpi-3.1.6
     AUTHOR_NAME Marty Kandes
     AUTHOR_EMAIL mkandes@sdsc.edu
 
-    LAST_UPDATED 20201228
+    LAST_UPDATED 20210803
 
 %setup
 

definition-files/ubuntu/Singularity.ubuntu-18.04-openmpi-3.1.6

-Bootstrap: shub
-From: mkandes/naked-singularity:ubuntu-18.04
+Bootstrap: oras
+From: ghcr.io/mkandes/naked-singularity:ubuntu-18.04
 
 %labels
 
@@ -10,7 +10,7 @@ From: mkandes/naked-singularity:ubuntu-18.04
     AUTHOR_NAME Marty Kandes
     AUTHOR_EMAIL mkandes@sdsc.edu
 
-    LAST_UPDATED 20210409
+    LAST_UPDATED 20210803
 
 %setup