Removed debian backports from dockerfile

.github/workflows/erlang.yml

@@ -8,7 +8,7 @@ jobs:
     name: OTP ${{matrix.otp}}
     strategy:
       matrix:
-        otp: [21.3.8]
+        otp: [21.3.8.17]
         ruby: [2.6.3]
     steps:
       - uses: actions/checkout@v2.0.0

Dockerfile

@@ -8,7 +8,7 @@ RUN apt-get update && apt-get -t buster install -y -qq wget \
   && rm -rf /var/lib/apt/lists/*
 
 
-RUN apt-get update && apt-get -t buster-backports install -y -qq git \
+RUN apt-get update && apt-get install -y -qq git \
   && apt-get clean \
   && rm -rf /var/lib/apt/lists/*